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Sample records for nerve head biomechanics

  1. Optic nerve head biomechanics in aging and disease.

    Science.gov (United States)

    Downs, J Crawford

    2015-04-01

    This nontechnical review is focused upon educating the reader on optic nerve head biomechanics in both aging and disease along two main themes: what is known about how mechanical forces and the resulting deformations are distributed in the posterior pole and ONH (biomechanics) and what is known about how the living system responds to those deformations (mechanobiology). We focus on how ONH responds to IOP elevations as a structural system, insofar as the acute mechanical response of the lamina cribrosa is confounded with the responses of the peripapillary sclera, prelaminar neural tissues, and retrolaminar optic nerve. We discuss the biomechanical basis for IOP-driven changes in connective tissues, blood flow, and cellular responses. We use glaucoma as the primary framework to present the important aspects of ONH biomechanics in aging and disease, as ONH biomechanics, aging, and the posterior pole extracellular matrix (ECM) are thought to be centrally involved in glaucoma susceptibility, onset and progression.

  2. Integrated Model of the Eye/Optic Nerve Head Biomechanical Environment

    Science.gov (United States)

    Ethier, C. R.; Feola, A.; Myers, J. G.; Nelson, E.; Raykin, J.; Samuels, B.

    2017-01-01

    Visual Impairment and Intracranial Pressure (VIIP) syndrome is a concern for long-duration space flight. Previously, it has been suggested that ocular changes observed in VIIP syndrome are related to the cephalad fluid shift that results in altered fluid pressures [1]. We are investigating the impact of changes in intracranial pressure (ICP) using a combination of numerical models, which simulate the effects of various environment conditions, including finite element (FE) models of the posterior eye. The specific interest is to understand how altered pressures due to gravitational changes affect the biomechanical environment of tissues of the posterior eye and optic nerve sheath. METHODS: Additional description of the numerical modeling is provided in the IWS abstract by Nelson et al. In brief, to simulate the effects of a cephalad fluid shift on the cardiovascular and ocular systems, we utilized a lumped-parameter compartment model of these systems. The outputs of this lumped-parameter model then inform boundary conditions (pressures) for a finite element model of the optic nerve head (Figure 1). As an example, we show here a simulation of postural change from supine to 15 degree head-down tilt (HDT), with primary outcomes being the predicted change in strains at the optic nerve head (ONH) region, specifically in the lamina cribrosa (LC), retrolaminar optic nerve, and prelaminar neural tissue (PLNT). The strain field can be decomposed into three orthogonal components, denoted as the first, second and third principal strains. We compare the peak tensile (first principal) and compressive (third principal) strains, since elevated strain alters cell phenotype and induces tissue remodeling. RESULTS AND CONCLUSIONS: Our lumped-parameter model predicted an IOP increase of c. 7 mmHg after 21 minutes of 15 degree HDT, which agreed with previous reports of IOP in HDT [1]. The corresponding FEM simulations predicted a relative increase in the magnitudes of the peak tensile

  3. A porohyperelastic finite element model of the eye: the influence of stiffness and permeability on intraocular pressure and optic nerve head biomechanics.

    Science.gov (United States)

    Ayyalasomayajula, Avinash; Park, Robert I; Simon, Bruce R; Vande Geest, Jonathan P

    2016-01-01

    Progressively deteriorating visual field is a characteristic feature of primary open-angle glaucoma (POAG), and the biomechanics of optic nerve head (ONH) is believed to be important in its onset. We used porohyperelasticity to model the complex porous behavior of ocular tissues to better understand the effect variations in ocular material properties can have on ONH biomechanics. An axisymmetric model of the human eye was constructed to parametrically study how changes in the permeabilities of retina-Bruch's-choroid complex (k(RBC)), sclera k(sclera), uveoscleral pathway (k(UVSC)) and trabecular meshwork k(TM) as well as how changes in the stiffness of the lamina cribrosa (LC) and sclera affect IOP, LC strains, and translaminar interstitial pressure gradients (TLIPG). Decreasing k(RBC) from 5 × 10(- 12) to 5 × 10(- 13) m/s increased IOP and LC strains by 17%, and TLIPG by 21%. LC strains increased by 13% and 9% when the scleral and LC moduli were decreased by 48% and 50%, respectively. In addition to the trabecular meshwork and uveoscleral pathway, the retina-Bruch's-choroid complex had an important effect on IOP, LC strains, and TLIPG. Changes in k(RBC) and scleral modulus resulted in nonlinear changes in the IOP, and LC strains especially at the lowest k(TM) and k(UVSC). This study demonstrates that porohyperelastic modeling provides a novel method for computationally studying the biomechanical environment of the ONH. Porohyperelastic simulations of ocular tissues may help provide further insight into the complex biomechanical environment of posterior ocular tissues in POAG.

  4. Probabilistic Modeling of Intracranial Pressure Effects on Optic Nerve Biomechanics

    Science.gov (United States)

    Ethier, C. R.; Feola, Andrew J.; Raykin, Julia; Myers, Jerry G.; Nelson, Emily S.; Samuels, Brian C.

    2016-01-01

    Altered intracranial pressure (ICP) is involved/implicated in several ocular conditions: papilledema, glaucoma and Visual Impairment and Intracranial Pressure (VIIP) syndrome. The biomechanical effects of altered ICP on optic nerve head (ONH) tissues in these conditions are uncertain but likely important. We have quantified ICP-induced deformations of ONH tissues, using finite element (FE) and probabilistic modeling (Latin Hypercube Simulations (LHS)) to consider a range of tissue properties and relevant pressures.

  5. Biomechanical properties of peripheral nerve after acellular treatment

    Institute of Scientific and Technical Information of China (English)

    MA Xin-long; SUN Xiao-lei; YANG Zhao; LI Xiu-lan; MA Jian-xiong; ZHANG Yang; YUAN Zhen-zhen

    2011-01-01

    Background Peripheral nerve injury causes a high rate of disability and a huge economic burden,and is currently one of the serious health problems in the world.The use of nerve grafts plays a vital role in repairing nerve defects.Acellular nerve grafts have been widely used in many experimental models as a peripheral nerve substitute.The purpose of this study was to test the biomechanical properties of acellular nerve grafts.Methods Thirty-four fresh sciatic nerves were obtained from 17 adult male Wistar rats (age of 3 months) and randomly assigned to 3 groups:normal control group,nerve segments underwent no treatment and were put in phosphate buffered saline (pH 7.4) and stored at 4℃ until further use; physical method group,nerve segments were frozen at -196℃ and then thawed at 37℃; and chemical method group,nerve segments were chemically extracted with the detergents Triton X-200,sulfobetaine-10 (SB-10) and sulfobetaine-16 (SB-16).After the acellularization process was completed,the structural changes of in the sciatic nerves in each group were observed by hematoxylin-eosin staining and field emission scanning electron microscopy,then biomechanical properties were tested using a mechanical apparatus (Endura TEC ELF 3200,Bose,Boston,USA).Results Hematoxylin-eosin staining and field emission scanning electron microscopy demonstrated that the effects of acellularization,demyelination,and integrity of nerve fiber tube of the chemical method were better than that of the physical method.Biomechanical testing showed that peripheral nerve grafts treated with the chemical method resulted in some decreased biomechanical properties (ultimate load,ultimate stress,ultimate strain,and mechanical work to fracture) compared with normal control nerves,but the differences were not statistically significant (P >0.05).Conclusion Nerve treated with the chemical method may be more appropriate for use in implantation than nerve treated with the physical method.

  6. Dynamic biomechanics of the human head in lateral impacts

    OpenAIRE

    Zhang, Jiangyue; Yoganandan, Narayan; Pintar, Frank A.

    2009-01-01

    The biomechanical responses of human head (translational head CG accelerations, rotational head accelerations, and HIC) under lateral impact to the parietal-temporal region were investigated in the current study. Free drop tests were conducted at impact velocities ranging from 2.44 to 7.70 m/s with a 40 durometer, a 90 durometer flat padding, and a 90 durometer cylinder. Specimens were isolated from PMHS subjects at the level of occipital condyles, and the intracranial substance was replaced ...

  7. Cranial nerve injury after minor head trauma.

    Science.gov (United States)

    Coello, Alejandro Fernández; Canals, Andreu Gabarrós; Gonzalez, Juan Martino; Martín, Juan José Acebes

    2010-09-01

    There are no specific studies about cranial nerve (CN) injury following mild head trauma (Glasgow Coma Scale Score 14-15) in the literature. The aim of this analysis was to document the incidence of CN injury after mild head trauma and to correlate the initial CT findings with the final outcome 1 year after injury. The authors studied 49 consecutive patients affected by minor head trauma and CN lesions between January 2000 and January 2006. Detailed clinical and neurological examinations as well as CT studies using brain and bone windows were performed in all patients. Based on the CT findings the authors distinguished 3 types of traumatic injury: no lesion, skull base fracture, and other CT abnormalities. Patients were followed up for 1 year after head injury. The authors distinguished 3 grades of clinical recovery from CN palsy: no recovery, partial recovery, and complete recovery. Posttraumatic single nerve palsy was observed in 38 patients (77.6%), and multiple nerve injuries were observed in 11 (22.4%). Cranial nerves were affected in 62 cases. The most affected CN was the olfactory nerve (CN I), followed by the facial nerve (CN VII) and the oculomotor nerves (CNs III, IV, and VI). When more than 1 CN was involved, the most frequent association was between CNs VII and VIII. One year after head trauma, a CN deficit was present in 26 (81.2%) of the 32 cases with a skull base fracture, 12 (60%) of 20 cases with other CT abnormalities, and 3 (30%) of 10 cases without CT abnormalities. Trivial head trauma that causes a minor head injury (Glasgow Coma Scale Score 14-15) can result in CN palsies with a similar distribution to moderate or severe head injuries. The CNs associated with the highest incidence of palsy in this study were the olfactory, facial, and oculomotor nerves. The trigeminal and lower CNs were rarely damaged. Oculomotor nerve injury can have a good prognosis, with a greater chance of recovery if no lesion is demonstrated on the initial CT scan.

  8. Dynamic biomechanics of the human head in lateral impacts.

    Science.gov (United States)

    Zhang, Jiangyue; Yoganandan, Narayan; Pintar, Frank A

    2009-10-01

    The biomechanical responses of human head (translational head CG accelerations, rotational head accelerations, and HIC) under lateral impact to the parietal-temporal region were investigated in the current study. Free drop tests were conducted at impact velocities ranging from 2.44 to 7.70 m/s with a 40 durometer, a 90 durometer flat padding, and a 90 durometer cylinder. Specimens were isolated from PMHS subjects at the level of occipital condyles, and the intracranial substance was replaced with brain simulant (Sylgard 527). Three tri-axial accelerometers were instrumented at the anterior, posterior, and vertex of the specimen, and a pyramid nine accelerometer package (pNAP) was used at the contra-lateral site. Biomechanical responses were computed by transforming accelerations measured at each location to the head CG. The results indicated significant "hoop effect" from skull deformation. Translational head CG accelerations were accurately measured by transforming the pNAP, the vertex accelerations, or the average of anterior/posterior acceleration to the CG. The material stiffness and structural rigidity of the padding changed the biomechanical responses of the head with stiffer padding resulting in higher head accelerations. At the skull fracture, HIC values were more than 2-3x higher than the frontal skull fracture threshold (HIC=1000), emphasizing the differences between frontal and lateral impact. Rotational head accelerations up to 42.1 krad/s(2) were observed before skull fracture, indicating possible severe brain injury without skull fracture in lateral head impact. These data will help to establish injury criteria and threshold in lateral impacts for improved automotive protection and help clinicians understand the biomechanics of lateral head impact from improved diagnosis.

  9. Microgravity-Driven Optic Nerve/Sheath Biomechanics Simulations

    Science.gov (United States)

    Ethier, C. R.; Feola, A.; Myers, J. G.; Nelson, E.; Raykin, J.; Samuels, B.

    2016-01-01

    Visual Impairment and Intracranial Pressure (VIIP) syndrome is a concern for long-duration space flight. Current thinking suggests that the ocular changes observed in VIIP syndrome are related to cephalad fluid shifts resulting in altered fluid pressures [1]. In particular, we hypothesize that increased intracranial pressure (ICP) drives connective tissue remodeling of the posterior eye and optic nerve sheath (ONS). We describe here finite element (FE) modeling designed to understand how altered pressures, particularly altered ICP, affect the tissues of the posterior eye and optic nerve sheath (ONS) in VIIP. METHODS: Additional description of the modeling methodology is provided in the companion IWS abstract by Feola et al. In brief, a geometric model of the posterior eye and optic nerve, including the ONS, was created and the effects of fluid pressures on tissue deformations were simulated. We considered three ICP scenarios: an elevated ICP assumed to occur in chronic microgravity, and ICP in the upright and supine positions on earth. Within each scenario we used Latin hypercube sampling (LHS) to consider a range of ICPs, ONH tissue mechanical properties, intraocular pressures (IOPs) and mean arterial pressures (MAPs). The outcome measures were biomechanical strains in the lamina cribrosa, optic nerve and retina; here we focus on peak values of these strains, since elevated strain alters cell phenotype and induce tissue remodeling. In 3D, the strain field can be decomposed into three orthogonal components, denoted as first, second and third principal strains. RESULTS AND CONCLUSIONS: For baseline material properties, increasing ICP from 0 to 20 mmHg significantly changed strains within the posterior eye and ONS (Fig. 1), indicating that elevated ICP affects ocular tissue biomechanics. Notably, strains in the lamina cribrosa and retina became less extreme as ICP increased; however, within the optic nerve, the occurrence of such extreme strains greatly increased as

  10. Head-Neck Biomechanics in Simulated Rear Impact

    OpenAIRE

    Yoganandan, Narayan; Pintar, Frank A.; Cusick, Joseph F.; Kleinberger, Michael

    1998-01-01

    The first objective of this study is to present an overview of the human cadaver studies aimed to determine the biomechanics of the head-neck in a simulated rear crash. The need for kinematic studies to better understand the mechanisms of load transfer to the human head-neck complex is emphasized. Based on this need, a methodology is developed to delineate the dynamic kinematics of the human head-neck complex. Intact human cadaver head-neck complexes were subjected to postero-anterior impact ...

  11. Biomechanical properties of acellular sciatic nerves treated with a modified chemical method

    Institute of Scientific and Technical Information of China (English)

    Xinlong Ma; Zhao Yang; Xiaolei Sun; Jianxiong Ma; Xiulan Li; Zhenzhen Yuan; Yang Zhang; Honggang Guo

    2011-01-01

    Nerve grafts are able to adapt to surrounding biomechanical environments if the nerve graft itself exhibits appropriate biomechanical properties (load, elastic modulus, etc.). The present study was designed to determine the differences in biomechanical properties between fresh and chemically acellularized sciatic nerve grafts. Two different chemical methods were used to establish acellular nerve grafts. The nerve was chemically extracted in the Sondell method with a combination of Triton X-100 (nonionic detergent) and sodium deoxycholate (anionic detergent), and in the modified method with a combination of Triton X-200 (anionic detergent), sulfobetaine-10 (SB-10, amphoteric detergents), and sulfobetaine-16 (SB-16, amphoteric detergents). Following acellularization, hematoxylin-eosin staining and scanning electron microscopy demonstrated that the effect of acellularization via the modified method was similar to the traditional Sondell method. However, effects of demyelination and nerve fiber tube integrity were superior to the traditional Sondell method. Biomechanical testing showed that peripheral nerve graft treated using the chemical method resulted in decreased biomechanical properties (ultimate load, ultimate stress, ultimate strain, and mechanical work to fracture) compared with fresh nerves, but the differences had no statistical significance (P > 0.05). These results demonstrated no significant effect on biomechanical properties of nerves treated using the chemical method. In conclusion, nerve grafts treated via the modified method removed Schwann cells, preserved neural structures, and ensured biomechanical properties of the nerve graft, which could be more appropriate for implantation studies.

  12. Intracranial Pressure Influences the Behavior of the Optic Nerve Head.

    Science.gov (United States)

    Hua, Yi; Tong, Junfei; Ghate, Deepta; Kedar, Sachin; Gu, Linxia

    2017-03-01

    In this work, the biomechanical responses of the optic nerve head (ONH) to acute elevations in intracranial pressure (ICP) were systematically investigated through numerical modeling. An orthogonal experimental design was developed to quantify the influence of ten input factors that govern the anatomy and material properties of the ONH on the peak maximum principal strain (MPS) in the lamina cribrosa (LC) and postlaminar neural tissue (PLNT). Results showed that the sensitivity of ONH responses to various input factors was region-specific. In the LC, the peak MPS was most strongly dependent on the sclera thickness, LC modulus, and scleral canal size, whereas in the PLNT, the peak MPS was more sensitive to the scleral canal size, neural tissue modulus, and pia mater modulus. The enforcement of clinically relevant ICP in the retro-orbital subarachnoid space influenced the sensitivity analysis. It also induced much larger strains in the PLNT than in the LC. Moreover, acute elevation of ICP leads to dramatic strain distribution changes in the PLNT, but had minimal impact on the LC. This work could help to better understand patient-specific responses, to provide guidance on biomechanical factors resulting in optic nerve diseases, such as glaucoma, papilledema, and ischemic optic neuropathy, and to illuminate the possibilities for exploiting their potential to treat and prevent ONH diseases.

  13. Ulnar Head Replacement and Related Biomechanics

    Science.gov (United States)

    Sauerbier, Michael; Arsalan-Werner, Annika; Enderle, Elena; Vetter, Miriam; Vonier, Daniel

    2013-01-01

    A stable distal radioulnar joint (DRUJ) is mandatory for the function and load transmission in the wrist and forearm. Resectional salvage procedures such as the Darrach procedure, Bowers arthroplasty, and Sauvé-Kapandji procedure include the potential risk of radioulnar instability and impingement, which can lead to pain and weakness. Soft tissue stabilizing techniques have only limited success rates in solving these problems. In an attempt to stabilize the distal forearm mechanically following ulnar head resection, various endoprostheses have been developed to replace the ulnar head. The prostheses can be used for secondary treatment of failed ulnar head resection, but they can also achieve good results in the primary treatment of osteoarthritis of the DRUJ. Our experience consists of twenty-five patients (follow-up 30 months) with DRUJ osteoarthritis who were treated with an ulnar head prosthesis, with improvement in pain, range of motion, and grip strength. An ulnar head prosthesis should be considered as a treatment option for a painful DRUJ. PMID:24436786

  14. Biomechanics of the Optic Nerve Sheath in VIIP Syndrome

    Science.gov (United States)

    Ethier, C. Ross; Raykin, Julia; Gleason, Rudy; Mulugeta, Lealem; Myers, Jerry; Nelson, Emily; Samuels, Brian C.

    2014-01-01

    Long-duration space flight carries the risk of developing Visual Impairment and Intracranial Pressure (VIIP) syndrome, a spectrum of ophthalmic changes including posterior globe flattening, choroidal folds, distension of the optic nerve sheath (ONS), optic nerve kinking and potentially permanent degradation of visual function. The slow onset of VIIP, its chronic nature, and certain clinical features strongly suggest that biomechanical factors acting on the ONS play a role in VIIP. Here we measure several relevant ONS properties needed to model VIIP biomechanics. The ONS (meninges) of fresh porcine eyes (n7) was reflected, the nerve proper was truncated near the sclera, and the meninges were repositioned to create a hollow cylinder of meningeal connective tissue attached to the posterior sclera. The distal end was cannulated, sealed, and pressure clamped (mimicking cerebrospinal fluid [CSF] pressure), while the eye was also cannulated for independent control of intraocular pressure (IOP). The meninges were inflated (CSF pressure cycling 7-50 mmHg) while ONS outer diameter was imaged. In another set of experiments (n4), fluid permeation rate across the meninges was recorded by observing the drainage of an elevated fluid reservoir (30 mmHg) connected to the meninges. The ONS showed behavior typical of soft tissues: viscoelasticity, with hysteresis in early preconditioning cycles and repeatable behavior after 4 cycles, and nonlinear stiffening, particularly at CSF pressures 15 mmHg (Figure). Tangent moduli measured from the loading curve were 372 101, 1199 358, and 2050 379 kPa (mean SEM) at CSF pressures of 7, 15 and 30 mmHg, respectively. Flow rate measurements through the intact meninges at 30mmHg gave a permeability of 1.34 0.46 lmincm2mmHg (mean SEM). The ONS is a tough, strain-stiffening connective tissue that is surprisingly permeable. The latter observation suggests that there could be significant CSF drainage through the ONS into the orbit, likely important

  15. The optic nerve head in glaucoma

    Directory of Open Access Journals (Sweden)

    Rupert RA Bourne

    2006-09-01

    Full Text Available ll types of glaucoma involve glaucomatous optic neuropathy. The key to detection and management of glaucoma is understanding how to examine the optic nerve head (ONH. This pictorial glossary addresses the following issues: how to examine the ONH; normal characteristics of the ONH; characteristics of a glaucomatous ONH; how to tell if the glaucomatous optic neuropathy is getting worse;‘pitfalls and pearls’.

  16. Biomechanical analysis of padding in child seats and head injury.

    Science.gov (United States)

    Kumaresan, Srirangam; Sances, Anthony; Carlin, Fred

    2002-01-01

    Head injury is a common finding for infants and young children involved in automobile accidents. Although the child restraint seats have increased the level of safety for the pediatric population, skull fracture and/or brain injury occur during the interaction between the child's head and interior of the car seats with no padding. The introduction of effective and sufficient padding may significantly reduce the head injury. The present study was designed to evaluate the biomechanical effects of padding in child seats to reduce the potential for head injury. A head drop test of a six-month old anthropomorphic dummy was conducted. The side of the dummy head impacted the interior wing of child car seats of relatively soft and stiff materials, and a rigid metal plate at velocities of 2.2, 4.5 and 6.7 m/s. In all tests, three types of padding environments were used (no padding, comfort foam, 16 to 19 mm polypropylene padding). All data were collected at 10 kHz and filtered. A total of 39 tests were conducted. The head injury criteria (HIC), and head acceleration, and head angular acceleration were obtained. The HIC was calculated over a 36 ms interval from the resultant tri-axial acceleration. The angular accelerations were derived from the angular velocity data. The head injury biomechanical parameters decreased with the addition of padding. The HIC, peak acceleration, and angular acceleration were reduced up to 91%, 80%, and 61% respectively. The present results emphasize the importance of energy absorbing padding to provide an improved safety environment in child car seats.

  17. Evaluation of a laboratory model of human head impact biomechanics.

    Science.gov (United States)

    Hernandez, Fidel; Shull, Peter B; Camarillo, David B

    2015-09-18

    This work describes methodology for evaluating laboratory models of head impact biomechanics. Using this methodology, we investigated: how closely does twin-wire drop testing model head rotation in American football impacts? Head rotation is believed to cause mild traumatic brain injury (mTBI) but helmet safety standards only model head translations believed to cause severe TBI. It is unknown whether laboratory head impact models in safety standards, like twin-wire drop testing, reproduce six degree-of-freedom (6DOF) head impact biomechanics that may cause mTBI. We compared 6DOF measurements of 421 American football head impacts to twin-wire drop tests at impact sites and velocities weighted to represent typical field exposure. The highest rotational velocities produced by drop testing were the 74th percentile of non-injury field impacts. For a given translational acceleration level, drop testing underestimated field rotational acceleration by 46% and rotational velocity by 72%. Primary rotational acceleration frequencies were much larger in drop tests (~100 Hz) than field impacts (~10 Hz). Drop testing was physically unable to produce acceleration directions common in field impacts. Initial conditions of a single field impact were highly resolved in stereo high-speed video and reconstructed in a drop test. Reconstruction results reflected aggregate trends of lower amplitude rotational velocity and higher frequency rotational acceleration in drop testing, apparently due to twin-wire constraints and the absence of a neck. These results suggest twin-wire drop testing is limited in modeling head rotation during impact, and motivate continued evaluation of head impact models to ensure helmets are tested under conditions that may cause mTBI. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Anatomy of the optic nerve head and glaucomatous optic neuropathy.

    Science.gov (United States)

    Radius, R L

    1987-01-01

    The mechanism of axon damage in eyes with glaucomatous optic neuropathy remains undefined. Interestingly, it has been observed that, although the entire nerve cross-section may be involved by the nerve damage, in many instances, the superior and inferior axon bundles are preferentially affected by the pressure insult. Thus, recent studies by many investigators have stressed a re-examination of the optic nerve head anatomy, including the nerve head microcirculation, the glial and connective tissue elements within the nerve head, and the morphology of the axons themselves. Any correlation between regional differences in this anatomy and the preferential involvement by specific axon bundles within the nerve head by the pressure insult may suggest some further insight into the mechanisms underlying the pressure-induced axon loss in glaucomatous eyes.

  19. Unusual nerve supply of biceps from ulnar nerve and median nerve and a third head of biceps

    Directory of Open Access Journals (Sweden)

    Arora L

    2006-01-01

    Full Text Available Variations in branching pattern of the brachial plexus are common and have been reported by several investigators. Of the four main nerves traversing the arm, namely median, ulnar, radial and musculocutaneous, the ulnar and median nerve do not give any branches to muscles of the arm. Ulnar nerve after taking origin from medial cord of brachial plexus runs distally through axilla on medial side of axillary artery till middle of arm, where it pierces the medial intermuscular septum and enters the posterior compartment of arm. Ulnar nerve enters forearm between two heads of flexor carpi ulnaris from where it continues further. It supplies flexor carpi ulnaris , flexor digitorum profundus and several intrinsic muscles of hand . We recently observed dual supply of biceps muscle from ulnar and median nerves in arm. Musculocutaneous nerve was absent. Although communications between nerves in arm is rare, the communication between median nerve and musculocutaneous nerve were described from the 19th century which could explain innervation of biceps from median nerve. But no accurate description of ulnar nerve supplying biceps could be found in literature. Knowledge of anatomical variation of these nerves at level of upper arm is essential in light of the frequency with which surgery is performed to transfer nerve fascicles from ulnar nerve to biceps in case of brachial plexus injuries. We also observed third head of biceps, our aim is to describe the exact topography of this variation and to discuss its morphological.

  20. The optic nerve head in hereditary optic neuropathies.

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    O'Neill, Evelyn C; Mackey, David A; Connell, Paul P; Hewitt, Alex W; Danesh-Meyer, Helen V; Crowston, Jonathan G

    2009-05-01

    Hereditary optic neuropathies are a prominent cause of blindness in both children and adults. The disorders in this group share many overlapping clinical characteristics, including morphological changes that occur at the optic nerve head. Accurate and prompt clinical diagnosis, supplemented with imaging when indicated, is essential for optimum management of the relevant optic neuropathy and appropriate counseling of the patient on its natural history. Patient history, visual field assessment, optic disc findings and imaging are the cornerstones of a correct diagnosis. This Review highlights the characteristic optic nerve head features that are common to the various hereditary optic neuropathies, and describes the features that enable the conditions to be differentiated.

  1. The state of head injury biomechanics: past, present, and future part 2: physical experimentation.

    Science.gov (United States)

    Goldsmith, Werner; Monson, Kenneth L

    2005-01-01

    This presentation is the continuation of the article published in Critical Reviews of Biomedical Engineering, 29(5-6), 2001. That issue contained topics dealing with components and geometry of the human head, classification of head injuries, some early experimental studies, and tolerance considerations. It then dealt with head motion and load characterization, investigations during the period from 1939 to 1966, injury causation and early modeling efforts, the 1966 Head Injury Conference and its sequels, mechanical properties of solid tissues, fluid characterization, and early investigation of the mechanical properties of cranial materials. It continued with a description of the systematic investigations of solid cranial components and structural properties since 1966, fetal cranial properties, analytical head modeling, and numerical solutions of head injury. The paper concluded with experimental dynamic loading of human living and cadaver heads, dynamic loading of surrogate heads, and head injury mechanics. This portion of the paper describes physical head injury experimentation involving animals, primarily primates, human cadavers, volunteers, and inanimate physical models. In order to address the entire domain of head injury biomechanics in the two-part survey, it was intended that this information be supplemented by discussions of head injury tolerance and criteria, automotive and sports safety considerations, and the design of protective equipment, but Professor Goldsmith passed away before these sections could be completed. It is nevertheless anticipated that this attenuated installment will provide, in conjunction with the first part of the survey, a valuable resource for students and practitioners of head injury biomechanics.

  2. Evaluation of the Optic Nerve Head in Glaucoma.

    Science.gov (United States)

    Gandhi, Monica; Dubey, Suneeta

    2013-01-01

    Glaucoma is an optic neuropathy leading to changes in the intrapaillary and parapaillary regions of the optic disk. Despite technological advances, clinical identification of optic nerve head characteristics remains the first step in diagnosis. Careful examination of the disk parameters including size, shape, neuroretinal rim shape and pallor; size of the optic cup in relation to the area of the disk; configuration and depth of the optic cup; ratios of cup-to-disk diameter and cup-to-disk area; presence and location of splinter-shaped hemorrhages; occurrence, size, configuration, and location of parapapillary chorioretinal atrophy; and visibility of the retinal nerve fiber layer (RNFL) is important to differentiate between the glaucomatous and nonglaucomatous optic neuropathy. How to cite this article: Gandhi M, Dubey S. Evaluation of the Optic Nerve Head in Glaucoma. J Current Glau Prac 2013;7(3):106-114.

  3. "Heading" and neck injuries in soccer: a review of biomechanics and potential long-term effects.

    Science.gov (United States)

    Mehnert, Michael J; Agesen, Thomas; Malanga, Gerard A

    2005-10-01

    Although soccer has a lower injury rate than does American football, injuries to the head and neck do occur. Indeed, soccer is classified as a contact sport. The potential for cervical injuries from the maneuver known as "heading" are of particular concern. This review provides a synopsis of soccer-related head and neck injuries, an overview of the biomechanics of trauma, and a rational approach to evaluating patients. This review was conducted to assess and evaluate existing literature on the biomechanics of the act of heading in soccer and the potential for acute and long-term injury to the head and neck. The resulting work is based on literature searches of the PubMed and Medline databases, textbook reviews, and bibliographies of articles and textbooks obtained during the search. Findings from several studies were summarized and critiqued. Biomechanics, anatomy, pathophysiology, and their relation to the act of heading in soccer were also synthesized into the discussion. Relevant studies of athletes in other sports where activity can affect the neck and head in a manner similar to heading were also considered. The act of heading in soccer involves the athlete's entire body, and studies have used electromyography to define the activity of neck musculature during heading. The majority of head and neck injuries in soccer occur secondary to impacts other than those that occur during heading, however, rare case reports of serious injury exist. Degenerative bony changes in the cervical spine of soccer players have been noted in a few studies, but the connection with heading is not well established. Data from research in other sports, particularly American football and rugby, suggest a predisposition to degenerative disease of the neck secondary to axial loading mechanisms; the exact relevance of these studies to heading and soccer is unclear. The complex biomechanics of heading in soccer are not completely defined, especially with regard to long-term effects on the

  4. Radial head fracture associated with posterior interosseous nerve injury

    Directory of Open Access Journals (Sweden)

    Bernardo Barcellos Terra

    Full Text Available ABSTRACT Fractures of the radial head and radial neck correspond to 1.7-5.4% of all fractures and approximately 30% may present associated injuries. In the literature, there are few reports of radial head fracture with posterior interosseous nerve injury. This study aimed to report a case of radial head fracture associated with posterior interosseous nerve injury. CASE REPORT: A male patient, aged 42 years, sought medical care after falling from a skateboard. The patient related pain and limitation of movement in the right elbow and difficulty to extend the fingers of the right hand. During physical examination, thumb and fingers extension deficit was observed. The wrist extension showed a slight radial deviation. After imaging, it became evident that the patient had a fracture of the radial head that was classified as grade III in the Mason classification. The patient underwent fracture fixation; at the first postoperative day, thumb and fingers extension was observed. Although rare, posterior interosseous nerve branch injury may be associated with radial head fractures. In the present case, the authors believe that neuropraxia occurred as a result of the fracture hematoma and edema.

  5. Bilateral abducens nerve and right facial nerve palsy occuring after head trauma

    Directory of Open Access Journals (Sweden)

    ismail Boyraz

    2016-06-01

    Full Text Available Lesions of the nervus abducens, the 6th cranial nerve tend to be rare, usually occur suddenly following head injuries. A 43-year-old male patient presented with a history of fall from a height due to an occupational accident on the date of 11.01.2014. Cranial tomography demonstrated bilateral epidural hematoma. The epidural hematoma was drained during the operation. After the surgery, eye examination showed no vision loss, except limited bilateral lateral gaze. When the patient was unable to walk due to diplopia, he was advised to close one eye. On the right side, there were findings suggesting central facial paralysis. There may be multiple cranial nerve damage following head injury. Therefore, all cranial nerves should be thoroughly examined. [J Contemp Med 2016; 6(2.000: 110-113

  6. Biomechanics of Heading a Soccer Ball: Implications for Player Safety

    Directory of Open Access Journals (Sweden)

    Charles F. Babbs

    2001-01-01

    Full Text Available To better understand the risk and safety of heading a soccer ball, the author created a set of simple mathematical models based upon Newton�s second law of motion to describe the physics of heading. These models describe the player, the ball, the flight of the ball before impact, the motion of the head and ball during impact, and the effects of all of these upon the intensity and the duration of acceleration of the head. The calculated head accelerations were compared to those during presumably safe daily activities of jumping, dancing, and head nodding and also were related to established criteria for serious head injury from the motor vehicle crash literature. The results suggest heading is usually safe but occasionally dangerous, depending on key characteristics of both the player and the ball. Safety is greatly improved when players head the ball with greater effective body mass, which is determined by a player�s size, strength, and technique. Smaller youth players, because of their lesser body mass, are more at risk of potentially dangerous headers than are adults, even when using current youth size balls. Lower ball inflation pressure reduces risk of dangerous head accelerations. Lower pressure balls also have greater “touch” and “playability”, measured in terms of contact time and contact area between foot and ball during a kick. Focus on teaching proper technique, the re-design of age-appropriate balls for young players with reduced weight and inflation pressure, and avoidance of head contact with fast, rising balls kicked at close range can substantially reduce risk of subtle brain injury in players who head soccer balls.

  7. Biomechanics of heading a soccer ball: implications for player safety.

    Science.gov (United States)

    Babbs, C F

    2001-08-08

    To better understand the risk and safety of heading a soccer ball, the author created a set of simple mathematical models based upon Newton's second law of motion to describe the physics of heading. These models describe the player, the ball, the flight of the ball before impact, the motion of the head and ball during impact, and the effects of all of these upon the intensity and the duration of acceleration of the head. The calculated head accelerations were compared to those during presumably safe daily activities of jumping, dancing, and head nodding and also were related to established criteria for serious head injury from the motor vehicle crash literature. The results suggest heading is usually safe but occasionally dangerous, depending on key characteristics of both the player and the ball. Safety is greatly improved when players head the ball with greater effective body mass, which is determined by a player"s size, strength, and technique. Smaller youth players, because of their lesser body mass, are more at risk of potentially dangerous headers than are adults, even when using current youth size balls. Lower ball inflation pressure reduces risk of dangerous head accelerations. Lower pressure balls also have greater "touch" and "playability", measured in terms of contact time and contact area between foot and ball during a kick. Focus on teaching proper technique, the re-design of age-appropriate balls for young players with reduced weight and inflation pressure, and avoidance of head contact with fast, rising balls kicked at close range can substantially reduce risk of subtle brain injury in players who head soccer balls.

  8. Biomechanics of head injury in olympic taekwondo and boxing.

    Science.gov (United States)

    Fife, G P; O'Sullivan, D; Pieter, W

    2013-12-01

    The purpose was to examine differences between taekwondo kicks and boxing punches in resultant linear head acceleration (RLA), head injury criterion (HIC15), peak head velocity, and peak foot and fist velocities. Data from two existing publications on boxing punches and taekwondo kicks were compared. For taekwondo head impacts a Hybrid II Crash Dummy (Hybrid II) head was instrumented with a tri-axial accelerometer mounted inside the Hybrid II head. The Hybrid II was fixed to a height-adjustable frame and fitted with a protective taekwondo helmet. For boxing testing, a Hybrid III Crash Dummy head was instrumented with an array of tri-axial accelerometers mounted at the head centre of gravity. Differences in RLA between the roundhouse kick (130.11±51.67 g) and hook punch (71.23±32.19 g, d = 1.39) and in HIC15 (clench axe kick: 162.63±104.10; uppercut: 24.10±12.54, d = 2.29) were observed. Taekwondo kicks demonstrated significantly larger magnitudes than boxing punches for both RLA and HIC.

  9. BIOMECHANICS OF HEAD INJURY IN OLYMPIC TAEKWONDO AND BOXING

    Science.gov (United States)

    Fife, G.P.; Pieter, W.

    2013-01-01

    Objective The purpose was to examine differences between taekwondo kicks and boxing punches in resultant linear head acceleration (RLA), head injury criterion (HIC15), peak head velocity, and peak foot and fist velocities. Data from two existing publications on boxing punches and taekwondo kicks were compared. Methods For taekwondo head impacts a Hybrid II Crash Dummy (Hybrid II) head was instrumented with a tri-axial accelerometer mounted inside the Hybrid II head. The Hybrid II was fixed to a height-adjustable frame and fitted with a protective taekwondo helmet. For boxing testing, a Hybrid III Crash Dummy head was instrumented with an array of tri-axial accelerometers mounted at the head centre of gravity. Results Differences in RLA between the roundhouse kick (130.11±51.67 g) and hook punch (71.23±32.19 g, d = 1.39) and in HIC15 (clench axe kick: 162.63±104.10; uppercut: 24.10±12.54, d = 2.29) were observed. Conclusions Taekwondo kicks demonstrated significantly larger magnitudes than boxing punches for both RLA and HIC. PMID:24744497

  10. The relationship between biomechanical-anthropometrical parameters and the force exerted on the head when heading free kicks in soccer.

    Science.gov (United States)

    Teymouri, Meghdad; Sadeghi, Heydar; Nabaei, Amir; Kasaeian, Amir

    2012-01-01

    Soccer is a contact sport in which the players are frequently faced with the risk of injury. It has been shown that the force exerted on the head during heading can be as much as 500-1200 Newton (N). The main objective of this study was to determine whether there was any relationship between the force exerted on the head and several biomechanical and anthropometrical parameters related to heading free kicks. A total of 16 semi-professional soccer players with at least 5 years experience participated in this study. The mean age, height, and weight of the study participants were 21.36 ± 5.67, 178 ± 5.99 cm, and 70.55 ± 8.55 kg, respectively. To measure the force exerted on the heads of the players, a pressure gauge was installed on their foreheads. Each participant was asked to defend the ball using the heading technique three times. A camera with a sampling frequency of 150 frames per second was used to record the moment of impact between the ball and head during each heading event. For each participant and replicate, the ball and head velocity (m/s) as well as the angular body changes (degrees) were calculated using MATLAB and AutoCAD softwares, respectively. Descriptive statistics, including means and standard deviations were used to describe the data. Pearson correlation coefficient (alpha = 0.05) was used to examine potential relationships between the variables of interest. Significant correlations existed between the force exerted on the head during heading, participant age, body mass, body fat percentage, and head perimeter (P heading, such as age and head perimeter. Therefore, it was concluded that these variables should be considered when teaching and practicing the heading technique with players of different ages and anthropometric sizes.

  11. Cervical biomechanics and neck pain of "head-spinning" breakdancers.

    Science.gov (United States)

    Kauther, M D; Piotrowski, M; Hussmann, B; Lendemans, S; Wedemeyer, C; Jaeger, M

    2014-05-01

    The cervical spine of breakdancers is at great risk due to reversed body loading during headspin manoeuvers. This study focused on the cervical biomechanics of breakdancers and a correlation with neck pain. A standardized interview and biomechanical testing of the cervical spine of 25 participants with "headspin" ability ages 16-34 years and an age-matched cohort of 25 participants without any cervical spine problems was conducted. Neck pain history, Neck Disability Index (NDI), cervical range of motion (CROM) and cervical torque were recorded. The "headspin" group reported significantly better subjective fitness, more cervical complaints, higher pain intensity, a longer history of neck pain and a worse NDI compared to the "normal" collective. The "headspin" group showed a 2-2.5 times higher rate of neck pain than the normal population, with increased cervical flexion (pcervical torque in all planes (p<0.001). The CROM showed a negative moderate to strong correlation with NDI, pain intensity and history of neck pain. Sports medicine practitioners should be aware of headspin maneuver accidents that pose the risk of fractures, dislocations and spinal cord injuries of breakdancers.

  12. The effect of visual and sensory performance on head impact biomechanics in college football players.

    Science.gov (United States)

    Harpham, Jacqueline A; Mihalik, Jason P; Littleton, Ashley C; Frank, Barnett S; Guskiewicz, Kevin M

    2014-01-01

    The development of prevention strategies is critical to address the rising prevalence of sport-related concussions. Visual and sensory performance may influence an individual's ability to interpret environmental cues, anticipate opponents' actions, and create appropriate motor responses limiting the severity of an impending head impact. The purpose of this study was to determine the relationship between traditional and visual sensory reaction time measures, and the association between visual and sensory performance and head impact severity in college football players. Thirty-eight collegiate football players participated in the study. We used real-time data collection instrumentation to record head impact biomechanics during games and practices. Our findings reveal no significant correlations between reaction time on traditional and visual sensory measures. We found a significant association between head impact severity and level of visual and sensory performance for multiple assessments, with low visual and sensory performers sustaining a higher number of severe head impacts. Our findings reveal a link between level of visual and sensory performance and head impact biomechanics. Future research will allow clinicians to have the most appropriate testing batteries to identify at-risk athletes and create interventions to decrease their risk of injurious head impacts.

  13. Biomechanics of Head, Neck, and Chest Injury Prevention for Soldiers

    Science.gov (United States)

    2011-03-01

    magnitude filter was applied to the images. Bones with small articular spaces (such as cervical vertebra ) were manually separated. The polygon surfaces...the neck. Cervical vertebrae 1 through 7, the hyoid bone, the C2 cartilage, spinal cord, 52 muscles of the neck (listed in Figure 12 and Figure 13...studies of the cervical spine is provided in place the head supported mass analysis (Task 2.1/2.2), as agreed upon with USAARL. Task 3 includes the finite

  14. The Impact of Ocular Pressures, Material Properties and Geometry on Optic Nerve Head Deformation

    Science.gov (United States)

    Feola, Andrew J.; Myers, Jerry G.; Raykin, Julia; Nelson, Emily S.; Samuels, Brian C.; Ethier C. Ross

    2017-01-01

    Alteration in intracranial pressure (ICP) has been associated with various diseases that cause visual impairment, including glaucoma, idiopathic intracranial hypertension and Visual Impairment and Intracranial Pressure (VIIP) syndrome. However, how changes in ICP lead to vision loss is unclear, although it is hypothesized to involve deformations of the tissues in the optic nerve head (ONH). Recently, understanding the effect of ICP alterations on ocular tissues has become a major concern for NASA, where 42 of astronauts that partake in long duration space missions suffer from VIIP syndrome. Astronauts with VIIP syndrome suffer from visual impairment and changes in ocular anatomy that persist after returning to earth (1). It is hypothesized that the cephalad fluid shift that occurs upon entering microgravity increases ICP, which leads to an altered biomechanical environment in the posterior globe and optic nerve sheath, and subsequently VIIP syndrome. Our goal was to develop a finite element (FE) model to simulate the acute effects of elevated ICP on the posterior eye. Here, we simulated how inter-individual differences affect the deformation of ONH tissues. Further, we examined how several different geometries influenced deformations when exposed to elevated ICP.

  15. Four-headed biceps brachii muscle with variant course of musculocutaneous nerve: anatomical and clinical insight

    Directory of Open Access Journals (Sweden)

    Aggarwal A

    2009-10-01

    Full Text Available A rare case of four-headed biceps brachii muscle with variation in the course of musculocutaneous nerve was observed in left arm of a 48-year-old embalmed male cadaver. One of the extra head (third was fleshy throughout, originated from anteromedial surface of shaft of humerus and merged with the deep surface of short head. Fourth thin tendinous head originated just below lesser tuberosity of humerus and joined with the third head. Both accessory heads were lying under cover of short head of biceps. Musculocutaneous nerve was coursing between two supernumerary heads and subsequently between third head and short head of biceps brachii muscle. Origin of third head from shaft of humerus led to passage of nerve between this head and short head, before acquiring normal position between biceps brachii and brachialis muscles, and emerging out as lateral cutaneous nerve of forearm. Intramuscular course of nerve may be a potential site for nerve compression by hypertrophied biceps associated with strenuous regular physical activity of biceps or weight lifting.

  16. Biomechanics of chiasmal compression: Sensitivity of the mechanical behaviors of nerve fibers to variations in material property and geometry

    Science.gov (United States)

    Wang, Xiaofei; Neely, Andrew J.; McIlwaine, Gawn G.; Lueck, Christian J.

    2016-05-01

    The mechanism of bitemporal hemianopia is still unclear. Previous research suggested that the nerve fiber packing pattern may contribute to the selective damage of nasal (crossed) nerve fibers. Numerical models were built using finite element modeling to study the biomechanics of optic nerve fibers. The sensitivity of the mechanical behaviors of the nerve fibers to variations of five parameters in the nerve fiber model were investigated using design of experiments (DOE). Results show that the crossing angle is a very significant factor that affects a wide range of responses of the model. The strain difference between the crossed and the uncrossed nerve fibers may account for the phenomenon of bitemporal hemianopia. This work also highlights the need for more accurate material properties of the tissues in the model and an improved understanding of the microstructure of the optic chiasm.

  17. Biomechanical studies in an ovine model of non-accidental head injury.

    Science.gov (United States)

    Anderson, R W G; Sandoz, B; Dutschke, J K; Finnie, J W; Turner, R J; Blumbergs, P C; Manavis, J; Vink, R

    2014-08-22

    This paper presents the head kinematics of a novel ovine model of non-accidental head injury (NAHI) that consists only of a naturalistic oscillating insult. Nine, 7-to-10-day-old anesthetized and ventilated lambs were subjected to manual shaking. Two six-axis motion sensors tracked the position of the head and torso, and a triaxial accelerometer measured head acceleration. Animals experienced 10 episodes of shaking over 30 min, and then remained under anesthesia for 6h until killed by perfusion fixation of the brain. Each shaking episode lasted for 20s resulting in about 40 cycles per episode. Each cycle typically consisted of three impulsive events that corresponded to specific phases of the head's motion; the most substantial of these were interactions typically with the lamb's own torso, and these generated accelerations of 30-70 g. Impulsive loading was not considered severe. Other kinematic parameters recorded included estimates of head power transfer, head-torso flexion, and rate of flexion. Several styles of shaking were also identified across episodes and subjects. Axonal injury, neuronal reaction and albumin extravasation were widely distributed in the hemispheric white matter, brainstem and at the craniocervical junction and to a much greater magnitude in lower body weight lambs that died. This is the first biomechanical description of a large animal model of NAHI in which repetitive naturalistic insults were applied, and that reproduced a spectrum of injury associated with NAHI.

  18. Radial Head Subluxation After Malalignment of the Proximal Ulna: A Biomechanical Study.

    Science.gov (United States)

    Sandman, Emilie; Canet, Fanny; Petit, Yvan; Laflamme, George Y; Athwal, George S; Rouleau, Dominique M

    2014-08-01

    Understanding the anatomy of proximal ulna is important when treating complex injuries, since nonanatomic reconstruction may lead to malunion, arthrosis, and instability. The proximal ulna has a sagittal bow, termed the proximal ulna dorsal angulation (PUDA). The purpose of this study was to evaluate the magnitude of angular malalignment at the PUDA that would lead to radial head subluxation. This biomechanical study was conducted on 6 fresh frozen upper extremities with an elbow movement simulator. An osteotomy was performed at the PUDA and stabilized with internal fixation at 5 angles. Lateral elbow fluoroscopic images were taken in 4 elbow and 3 forearm positions, with the annular ligament intact and then released. The displacement of the radial head was quantified with the radiocapitellar ratio measurement. A significant interaction exists between elbow positions, angles of malalignment, and annular ligament integrity (P < 0.001). The greatest magnitudes of radial head subluxation were with annular ligament tear, ranging from -4% to 88% (P < 0.001). Significant differences were found between the different internal fixation angles (P = 0.002) and elbow positions (P < 0.001). Anterior subluxation increased as malalignment was fixed into extension and with progressive elbow flexion. Posterior subluxation increased as malalignment advanced into flexion and decreased with elbow flexion. Proximal ulna malalignment combined with an annular ligament tear affect the biomechanics of the elbow and can lead to radial head subluxation. This study demonstrates the importance of an anatomic reconstruction, specifically recreation of each individual's unique PUDA. Thus, in the setting of a comminuted proximal ulna fracture with associated annular ligament insufficiency, radiographs of the contralateral elbow may assist with the restoration of the normal anatomy to limit radial head instability.

  19. Ocular biomechanics study: current state and perspectives

    Directory of Open Access Journals (Sweden)

    S. Yu. Petrov

    2015-03-01

    Full Text Available Despite the fact that the eye represents a challenge for biomechanical research due to its size, over the last two decades, much data on ocular biomechanics were accumulated. Scleral and lamina cribrosa biomechanics contribute to our understanding of myopia and open-angle glaucoma; iris and trabecular meshwork biomechanics to that of angle-closure glaucoma; vitreous biomechanics to that of retinal detachment and ocular drug delivery; corneal biomechanics to that of keratoconus; and lens capsule biomechanics to that of cataract. This paper offers a general overview of recent advances in corneal, scleral, crystalline lens, and lamina cribrosa biomechanics and summarizes the results of experimental and clinical studies. Ocular biomechanics abnormalities affect etiology of many eye diseases. Ocular biomechanics plays an important role in the development of novel diagnostic methods, therapeutic and surgical procedures. Corneal biomechanics impacts etiology and pathogenesis of keratoconus as well as tonometry accuracy and explains corneal refractive surgery effect. Scleral biomechanics is associated with IOP and progressive myopia. Accommodative apparatus (ciliary body and crystalline lens is an important anatomic physiological structure. Recent studies uncovered the causes of agerelated loss of accommodation as a result of lens involution. Optic nerve head abnormalities due to IOP fluctuations are the key factor of glaucomatous neuropathy. They are directly associated with ocular biomechanics as well.

  20. Ocular biomechanics study: current state and perspectives

    Directory of Open Access Journals (Sweden)

    S. Yu. Petrov

    2015-01-01

    Full Text Available Despite the fact that the eye represents a challenge for biomechanical research due to its size, over the last two decades, much data on ocular biomechanics were accumulated. Scleral and lamina cribrosa biomechanics contribute to our understanding of myopia and open-angle glaucoma; iris and trabecular meshwork biomechanics to that of angle-closure glaucoma; vitreous biomechanics to that of retinal detachment and ocular drug delivery; corneal biomechanics to that of keratoconus; and lens capsule biomechanics to that of cataract. This paper offers a general overview of recent advances in corneal, scleral, crystalline lens, and lamina cribrosa biomechanics and summarizes the results of experimental and clinical studies. Ocular biomechanics abnormalities affect etiology of many eye diseases. Ocular biomechanics plays an important role in the development of novel diagnostic methods, therapeutic and surgical procedures. Corneal biomechanics impacts etiology and pathogenesis of keratoconus as well as tonometry accuracy and explains corneal refractive surgery effect. Scleral biomechanics is associated with IOP and progressive myopia. Accommodative apparatus (ciliary body and crystalline lens is an important anatomic physiological structure. Recent studies uncovered the causes of agerelated loss of accommodation as a result of lens involution. Optic nerve head abnormalities due to IOP fluctuations are the key factor of glaucomatous neuropathy. They are directly associated with ocular biomechanics as well.

  1. Oncologic safety of cervical nerve preservation in neck dissection for head and neck cancer.

    Science.gov (United States)

    Honda, Keigo; Asato, Ryo; Tsuji, Jun; Miyazaki, Masakazu; Kada, Shinpei; Tsujimura, Takashi; Kataoka, Michiko

    2017-09-01

    Although the functional merits of preserving cervical nerves in neck dissection for head and neck cancer have been reported, the oncologic safety has not yet been determined. Therefore, the purpose of this study was to evaluate the safety of cervical nerve preservation. A retrospective chart review was performed on patients with head and neck cancer who had been treated by neck dissection between 2009 and 2014 at Kyoto Medical Center. Management of cervical nerves and clinical results were analyzed. A total of 335 sides of neck dissection had been performed in 222 patients. Cervical nerves were preserved in 175 neck sides and resected in 160 sides. The 5-year overall survival (OS) rate calculated by the Kaplan-Meier method was 71%. The 5-year neck control rate was 95% in cervical nerve preserved sides and 89% in cervical nerve resected sides. Preserving cervical nerves in neck dissection is oncologically safe in selected cases. © 2017 Wiley Periodicals, Inc.

  2. Human umbilical cord blood stem cells and brain-derived neurotrophic factor for optic nerve injury:a biomechanical evaluation

    Institute of Scientific and Technical Information of China (English)

    Zhong-jun Zhang; Ya-jun Li; Xiao-guang Liu; Feng-xiao Huang; Tie-jun Liu; Dong-mei Jiang; Xue-man Lv; Min Luo

    2015-01-01

    Treatment for optic nerve injury by brain-derived neurotrophic factor or the transplantation of human umbilical cord blood stem cells has gained progress, but analysis by biomechanical indicators is rare. Rabbit models of optic nerve injury were established by a clamp. At 7 days after injury, the vitreous body received a one-time injection of 50 μg brain-derived neurotrophic factor or 1 × 106 human umbilical cord blood stem cells. After 30 days, the maximum load, max-imum stress, maximum strain, elastic limit load, elastic limit stress, and elastic limit strain had clearly improved in rabbit models of optical nerve injury after treatment with brain-derived neu-rotrophic factor or human umbilical cord blood stem cells. The damage to the ultrastructure of the optic nerve had also been reduced. These ifndings suggest that human umbilical cord blood stem cells and brain-derived neurotrophic factor effectively repair the injured optical nerve, im-prove biomechanical properties, and contribute to the recovery after injury.

  3. Pit-like changes of the optic nerve head in open-angle glaucoma.

    Science.gov (United States)

    Radius, R. L.; Maumenee, A. E.; Green, W. R.

    1978-01-01

    Six patients with open-angle glaucoma and acquired pit-like changes in the optic nerve head are presented. In 1 patient evolution of the pit-like defect is documented. In all 6 patients progression of associated visual field deficits is described. It is suggested that such pit-like changes in selected patients with glaucoma may not represent congenital lesions but rather local, progressive nerve head disease, occurring particularly in response to raised intraocular pressure. The management of patients with optic nerve head pitting and the pathogenesis of glaucomatous optic neuropathy are discussed with respect to this observation. Images PMID:666988

  4. Network analysis of human glaucomatous optic nerve head astrocytes

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    Bhattacharya Sanjoy K

    2009-05-01

    Full Text Available Abstract Background Astrocyte activation is a characteristic response to injury in the central nervous system, and can be either neurotoxic or neuroprotective, while the regulation of both roles remains elusive. Methods To decipher the regulatory elements controlling astrocyte-mediated neurotoxicity in glaucoma, we conducted a systems-level functional analysis of gene expression, proteomic and genetic data associated with reactive optic nerve head astrocytes (ONHAs. Results Our reconstruction of the molecular interactions affected by glaucoma revealed multi-domain biological networks controlling activation of ONHAs at the level of intercellular stimuli, intracellular signaling and core effectors. The analysis revealed that synergistic action of the transcription factors AP-1, vitamin D receptor and Nuclear Factor-kappaB in cross-activation of multiple pathways, including inflammatory cytokines, complement, clusterin, ephrins, and multiple metabolic pathways. We found that the products of over two thirds of genes linked to glaucoma by genetic analysis can be functionally interconnected into one epistatic network via experimentally-validated interactions. Finally, we built and analyzed an integrative disease pathology network from a combined set of genes revealed in genetic studies, genes differentially expressed in glaucoma and closely connected genes/proteins in the interactome. Conclusion Our results suggest several key biological network modules that are involved in regulating neurotoxicity of reactive astrocytes in glaucoma, and comprise potential targets for cell-based therapy.

  5. Biomechanical influences of head posture on occlusion: an experimental study using finite element analysis.

    Science.gov (United States)

    Motoyoshi, Mitsuru; Shimazaki, Takahisa; Sugai, Tatsuyoshi; Namura, Shinkichi

    2002-08-01

    The biomechanical influences of head posture on the cervical column and craniofacial complex during masticatory simulation were quantified using three-dimensional (3D) finite element analysis (FEA). Three types of finite element model (FEM) were designed to examine relationships between the position of the head and malocclusion. Model A was constructed to have a standardized cervical column curve, model B a forward inclined posture, and model C a backward inclined posture. The results of the spinal displacements revealed that model B moved in a forward direction and model C in a backward direction during masticatory simulation. The stress distributions on the cervical column (C1-C7) for models A, B, and C showed differences; stress converged at the atlas in model A, high-level stresses were observed at the spinous processes of C6 and C7 in model C, and the stress converged at the anterior edge in the vertebral body of C4 of model B. Stress distribution on the occlusal plane and maxillofacial structure did not show absolute differences among the three models. Alteration of head posture was directly related to stress distribution on the cervical column, but may not always directly influence the occlusal state.

  6. Integrins in Trabecular Meshwork and Optic Nerve Head: Possible Association with the Pathogenesis of Glaucoma

    Directory of Open Access Journals (Sweden)

    Yisheng Zhong

    2013-01-01

    Full Text Available Integrins are a family of membrane-spanning proteins that are important receptors for cell adhesion to extracellular matrix proteins. They also provide connections between the extracellular environment and intracellular cytoskeletons and are responsible for activation of many intracellular signaling pathways. In vitro and in vivo data strongly indicate that integrin-mediated signaling events can modulate the organization of the actin cytoskeleton in trabecular meshwork (TM cells and are associated with astrocyte migration and microglia activation of the optic nerve head in patients with primary open angle glaucoma. Consequently, increase in resistance in the TM outflow pathways and remodeling of the optic nerve head occur, which in turn increases intraocular pressure (IOP, adds additional mechanical stress and strain to optic nerve axons, and accelerates damage of axons initially caused by optic nerve head remodeling. Integrins appear to be ideal candidates for translating physical stress and strain into cellular responses known to occur in glaucomatous optic neuropathy.

  7. Dissection and Exposure of the Whole Course of Deep Nerves in Human Head Specimens after Decalcification

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    Longping Liu

    2012-01-01

    Full Text Available The whole course of the chorda tympani nerve, nerve of pterygoid canal, and facial nerves and their relationships with surrounding structures are complex. After reviewing the literature, it was found that details of the whole course of these deep nerves are rarely reported and specimens displaying these nerves are rarely seen in the dissecting room, anatomical museum, or atlases. Dissections were performed on 16 decalcified human head specimens, exposing the chorda tympani and the nerve connection between the geniculate and pterygopalatine ganglia. Measurements of nerve lengths, branching distances, and ganglia size were taken. The chorda tympani is a very fine nerve (0.44 mm in diameter within the tympanic cavity and approximately 54 mm in length. The mean length of the facial nerve from opening of internal acoustic meatus to stylomastoid foramen was 52.5 mm. The mean length of the greater petrosal nerve was 26.1 mm and nerve of the pterygoid canal was 15.1 mm.

  8. Optic nerve head and fibre layer imaging for diagnosing glaucoma

    Science.gov (United States)

    Michelessi, Manuele; Lucenteforte, Ersilia; Oddone, Francesco; Brazzelli, Miriam; Parravano, Mariacristina; Franchi, Sara; Ng, Sueko M; Virgili, Gianni

    2016-01-01

    Background The diagnosis of glaucoma is traditionally based on the finding of optic nerve head (ONH) damage assessed subjectively by ophthalmoscopy or photography or by corresponding damage to the visual field assessed by automated perimetry, or both. Diagnostic assessments are usually required when ophthalmologists or primary eye care professionals find elevated intraocular pressure (IOP) or a suspect appearance of the ONH. Imaging tests such as confocal scanning laser ophthalmoscopy (HRT), optical coherence tomography (OCT) and scanning laser polarimetry (SLP, as used by the GDx instrument), provide an objective measure of the structural changes of retinal nerve fibre layer (RNFL) thickness and ONH parameters occurring in glaucoma. Objectives To determine the diagnostic accuracy of HRT, OCT and GDx for diagnosing manifest glaucoma by detecting ONH and RNFL damage. Search methods We searched several databases for this review. The most recent searches were on 19 February 2015. Selection criteria We included prospective and retrospective cohort studies and case-control studies that evaluated the accuracy of OCT, HRT or the GDx for diagnosing glaucoma. We excluded population-based screening studies, since we planned to consider studies on self-referred people or participants in whom a risk factor for glaucoma had already been identified in primary care, such as elevated IOP or a family history of glaucoma. We only considered recent commercial versions of the tests: spectral domain OCT, HRT III and GDx VCC or ECC. Data collection and analysis We adopted standard Cochrane methods. We fitted a hierarchical summary ROC (HSROC) model using the METADAS macro in SAS software. After studies were selected, we decided to use 2 × 2 data at 0.95 specificity or closer in meta-analyses, since this was the most commonly-reported level. Main results We included 106 studies in this review, which analysed 16,260 eyes (8353 cases, 7907 controls) in total. Forty studies (5574

  9. Motor nerves of the head and neck that are susceptible to damage during dermatological surgery.

    Science.gov (United States)

    Brown, S M; Oliphant, T; Langtry, J

    2014-08-01

    As the incidence of non melanoma skin cancer rises, dermatologists will increasingly be called upon to perform excisions in the head and neck region. Damage to the motor nerves of the head and neck represents an important adverse event for patients, and a source of litigation for surgeons. Understanding the anatomy of this region is key to counselling patients about the possibility of motor nerve injury associated with particular skin surgical procedures. We describe the anatomy of the motor nerves of the head and neck that are most vulnerable to injury during dermatological surgery. The consequences of injury are outlined, and the surface anatomy and anatomical landmarks that may be used to identify the relevant danger zones are described.

  10. Drusen of the optic nerve head in CT imaging; Druzy tarczy nerwu wzrokowego w obrazie tomografii komputerowej

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    Kabula, S.; Stefaniak, E.; Burzynska-Makuch, M.; Boron, Z. [Akademia Medyczna, Bydgoszcz (Poland)

    1994-12-31

    The optic nerve head drusen are non-cell formations, which are almost always calcified. They have a characteristic feature in CT examination, what can be helpful in differentiation from calcifications of the other origin, located in the posterior globe. Authors present cases of the optic nerve head drusen with typical feature in CT examination. (author). 4 refs, 1 fig.

  11. Biomechanical-based image registration for head and neck radiation treatment

    Energy Technology Data Exchange (ETDEWEB)

    Al-Mayah, Adil; Moseley, Joanne; Hunter, Shannon; Velec, Mike; Chau, Lily; Breen, Stephen; Brock, Kristy, E-mail: adil.al-mayah@rmp.uhn.on.c [Radiation Medicine Program, Princess Margaret Hospital, 610 University Ave. Toronto, Ontario, M5G 2M9 (Canada)

    2010-11-07

    Deformable image registration of four head and neck cancer patients has been conducted using a biomechanical-based model. Patient-specific 3D finite element models have been developed using CT and cone-beam CT image data of the planning and a radiation treatment session. The model consists of seven vertebrae (C1 to C7), mandible, larynx, left and right parotid glands, tumor and body. Different combinations of boundary conditions are applied in the model in order to find the configuration with a minimum registration error. Each vertebra in the planning session is individually aligned with its correspondence in the treatment session. Rigid alignment is used for each individual vertebra and the mandible since no deformation is expected in the bones. In addition, the effect of morphological differences in the external body between the two image sessions is investigated. The accuracy of the registration is evaluated using the tumor and both parotid glands by comparing the calculated Dice similarity index of these structures following deformation in relation to their true surface defined in the image of the second session. The registration is improved when the vertebrae and mandible are aligned in the two sessions with the highest average Dice index of 0.86 {+-} 0.08, 0.84 {+-} 0.11 and 0.89 {+-} 0.04 for the tumor, left and right parotid glands, respectively. The accuracy of the center of mass location of tumor and parotid glands is also improved by deformable image registration where the errors in the tumor and parotid glands decrease from 4.0 {+-} 1.1, 3.4 {+-} 1.5 and 3.8 {+-} 0.9 mm using rigid registration to 2.3 {+-} 1.0, 2.5 {+-} 0.8 and 2.0 {+-} 0.9 mm in the deformable image registration when alignment of vertebrae and mandible is conducted in addition to the surface projection of the body.

  12. Unilateral compression neuropathy of the hypoglossal nerve due to head suspension orthosis in mitochondriopathy.

    Science.gov (United States)

    Finsterer, Josef; Hess, Barbara

    2004-12-01

    An 85-year-old woman with multisystem mitochondriopathy experienced tension headache, cervical pain, torque head-posture, and vertigo since 1980 for which she was continuously wearing a head-suspension-orthosis- since 1990. Since 1996 she developed severe left-sided weakness and wasting of the tongue. Needle-EMG of the left genioglossus muscle revealed abnormal spontaneous activity and reduced interference-pattern. No morphological alterations in the anatomical course of the hypoglossal nerve were found. Severe, unilateral weakness and wasting of the tongue was interpreted due to chronic compression of the hypoglossal nerve by long-standing use of a head-suspension-orthosis for cervical pain from cervical muscle weakness and resulting spinal degeneration.

  13. [Biomechanical properties of the cribriform lamina in glaucoma-induced atrophy of the optic nerve and after decompression operations on the scleral canal].

    Science.gov (United States)

    Mostovoĭ, E N; Shmyreva, V F; Kaĭdalov, A B

    2008-01-01

    The authors made a mathematical and clinical analysis of the cribriform lamina (CL) of the optic nerve and nerve fiber bundles passing through its foramens in glaucoma-induced optic neuropathy. It was shown that in elevated intraocular pressure, there was a significant CL deformity leading to the compression and deformity of nerve fibers. The important biomechanical characteristic of CL deformity is the tangent of the angle between the longitudinal axis of the scleral canal and the perpendicular to the CL surface. An increase in the inner radius of the scleral canal of the optic nerve due to its dissection at decompression surgery is one of the ways of diminishing CL flexure and nerve fiber deformity. A small increase in the scleral canal radius (by approximately 10%) was demonstrated to eliminate significant CL flexure.

  14. Concomitant abducens and facial nerve palsies following blunt head trauma associated with bone fracture.

    Science.gov (United States)

    Ji, Min-Jeong; Han, Sang-Beom; Lee, Seung-Jun; Kim, Moosang

    2015-07-15

    A 22-year-old man was referred for horizontal diplopia that worsened on left gaze. He had been admitted for a head trauma caused by a traffic accident. Brain CT scan showed a longitudinal fracture of the left temporal bone with extension to the left carotid canal and central skull base, including sphenoid lateral wall and roof, and left orbit medial wall non-displaced fracture. Prism cover test revealed 20 prism diopters of esotropia and abduction limitation in the left eye. Hess screening test results were compatible with left abducens nerve paralysis. Symptoms suggesting complete lower motor neuron palsy of the left facial nerve, such as unilateral facial drooping, inability to raise the eyebrow and difficulty closing the eye, were present. As there was no improvement in facial paralysis, the patient received surgical intervention using a transmastoidal approach. Three months postoperatively, prism cover test showed orthotropia, however, the facial nerve palsy persisted.

  15. The course of axons through the retina and optic nerve head.

    Science.gov (United States)

    Radius, R L; Anderson, D R

    1979-06-01

    By identifying degenerating axons in tissue specimens from 22 primate eyes, it was possible to demonstrate the normal course of axon fibers. Nerve fiber bundles from a group of retinal ganglion cells travel together with little tendency to disperse laterally. In addition, axons are stratified such that processes from more central ganglion cells are successfully added to the inner strata of the retinal nerve fiber layer. Within and behind the lamina cribrosa, areas of degeneration following retinal photocoagulation were well circumscribed and confined to a group of adjacent axon bundles. This degree of retinotopic organization of axons within the nerve head and retinal fiber layer is believed to be consistent with the premise that isolated lesions within the lamina cribrosa could cause well-organized paracentral scotomas such as those characteristic of early glaucoma.

  16. A biomechanical evaluation of proximal femoral nail antirotation with respect to helical blade position in femoral head: A cadaveric study

    Directory of Open Access Journals (Sweden)

    Jin-Ho Hwang

    2012-01-01

    Full Text Available Objective: Despite new developments in the management of osteoporotic fractures, complications like screw cutout are still found in the fixation of proximal femur fractures even with biomechanically proven better implants like proximal femoral nail antirotation (PFNA. The purpose of this cadaveric study was to investigate the biomechanical stability of this device in relation to two common positions (center-center and inferior-center of the helical blade in the femoral head in unstable trochanteric fractures. Materials and Methods: Eight pairs of human cadaveric femurs were used; in one group [center-center (C-C group], the helical blade of PFNA was fixed randomly in central position both in anteroposterior and lateral view, whereas in the other group it was fixed in inferior one-third position in anteroposterior and in central position in lateral view [inferior-center (I-C group]. Unstable intertrochanteric fracture was created and each specimen was loaded cyclically till load to failure Results: Angular and rotational displacements were significantly higher within the C-C group compared to the I-C group in both unloaded and loaded condition. Loading to failure was higher in the I-C group compared to the C-C group. No statistical significance was found for this parameter. Correlations between tip apex distance, cyclic loading which lead to femoral head displacement, and ultimate load to failure showed a significant positive relationship. Conclusion: The I-C group was superior to the C-C group and provided better biomechanical stability for angular and rotational displacement. This study would be a stimulus for further experimental studies with larger number specimens and complex loading protocols at multicentres.

  17. Assessment of the optic nerve head parameters using Heidelberg retinal tomography III in preterm children.

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    Salem Alshaarawi

    Full Text Available BACKGROUND: Variations in optic nerve head morphology and abnormal retinal vascular pattern have been described in preterm children using digital image analysis of fundus photograph, optical coherence tomograph and serial funduscopy. We aimed to compare the optic nerve head parameters in preterm and term Malay children using Heidelberg Retinal Tomograph III. DESIGN: A cross sectional study. METHODOLOGY/PRINCIPAL FINDINGS: Thirty-two preterm Malay children who were born at up to 32 weeks postconception, and 32 term Malay children aged 8-16 years old were recruited into this cross sectional study, which was conducted in the Hospital Universiti Sains Malaysia, Malaysia from January to December 2011. Their optic nerves were scanned and analyzed using a Heidelberg Retinal Tomography (HRT III (Heidelberg Engineering, Germany. Preterm children showed an increased rim volume (SD (0.56 (0.26 vs 0.44 (0.18 mm(3, respectively, smaller cup shape (SD (0.18 (0.07 vs 0.25 (0.06 mm, respectively, increased height variation contour (SD (0.44 (0.14 vs 0.35 (0.08 mm, respectively, and increased cup depth (SD (0.24 (0.11 vs 0.17 (0.05 mm(3, respectively when compared to their normal peers (p0.05 in our study. CONCLUSIONS/SIGNIFICANCE: Preterm children exhibit different characteristics of optic nerve head parameters with HRT III analysis. Increased cup depth in preterm children suggests a need for close observation and monitoring. It may raise suspicion of pediatric glaucoma when proper documentation of intraocular pressure and clinical funduscopy are unsuccessful in uncooperative children.

  18. Cervical Spine Muscle-Tendon Unit Length Differences Between Neutral and Forward Head Postures: Biomechanical Study Using Human Cadaveric Specimens.

    Science.gov (United States)

    Khayatzadeh, Saeed; Kalmanson, Olivia A; Schuit, Dale; Havey, Robert M; Voronov, Leonard I; Ghanayem, Alexander J; Patwardhan, Avinash G

    2017-07-01

    Forward head posture (FHP) may be associated with neck pain and poor health-related quality of life. Literature describes only qualitative muscle length changes associated with FHP. The purpose of this study was to quantify how muscle-tendon unit lengths are altered when human cadaveric specimens are placed in alignments representing different severities of FHP. This biomechanical study used 13 fresh-frozen cadaveric cervical spine specimens (Occiput-T1, 54±15 y). Specimens' postural changes simulating increasing FHP severity while maintaining horizontal gaze were assessed. Specimen-specific anatomic models derived from computed tomography-based anatomic data were combined with postural data and specimen-specific anatomy of muscle attachment points to estimate the muscle length changes associated with FHP. Forward head posture was associated with flexion of the mid-lower cervical spine and extension of the upper cervical (sub-occipital) spine. Muscles that insert on the cervical spine and function as flexors (termed "cervical flexors") as well as muscles that insert on the cranium and function as extensors ("occipital extensors") shortened in FHP when compared to neutral posture. In contrast, muscles that insert on the cervical spine and function as extensors ("cervical extensors") as well as muscles that insert on the cranium and function as flexors ("occipital flexors") lengthened. The greatest shortening was seen in the major and minor rectus capitis posterior muscles. These muscles cross the Occiput-C2 segments, which exhibited extension to maintain horizontal gaze. The greatest lengthening was seen in posterior muscles crossing the C4-C6 segments, which exhibited the most flexion. This cadaver study did not incorporate the biomechanical influence of active musculature. This study offers a novel way to quantify postural alignment and muscle length changes associated with FHP. Model predictions are consistent with qualitative descriptions in the literature.

  19. Tele-transmission of stereoscopic images of the optic nerve head in glaucoma via Internet.

    Science.gov (United States)

    Bergua, Antonio; Mardin, Christian Y; Horn, Folkert K

    2009-06-01

    The objective was to describe an inexpensive system to visualize stereoscopic photographs of the optic nerve head on computer displays and to transmit such images via the Internet for collaborative research or remote clinical diagnosis in glaucoma. Stereoscopic images of glaucoma patients were digitized and stored in a file format (joint photographic stereoimage [jps]) containing all three-dimensional information for both eyes on an Internet Web site (www.trizax.com). The size of jps files was between 0.4 to 1.4 MB (corresponding to a diagonal stereo image size between 900 and 1400 pixels) suitable for Internet protocols. A conventional personal computer system equipped with wireless stereoscopic LCD shutter glasses and a CRT-monitor with high refresh rate (120 Hz) can be used to obtain flicker-free stereo visualization of true-color images with high resolution. Modern thin-film transistor-LCD displays in combination with inexpensive red-cyan goggles achieve stereoscopic visualization with the same resolution but reduced color quality and contrast. The primary aim of our study was met to transmit stereoscopic images via the Internet. Additionally, we found that with both stereoscopic visualization techniques, cup depth, neuroretinal rim shape, and slope of the inner wall of the optic nerve head, can be qualitatively better perceived and interpreted than with monoscopic images. This study demonstrates high-quality and low-cost Internet transmission of stereoscopic images of the optic nerve head from glaucoma patients. The technique allows exchange of stereoscopic images and can be applied to tele-diagnostic and glaucoma research.

  20. Effects of Head-down Tilt on Nerve Conduction in Rhesus Monkeys

    Science.gov (United States)

    Sun, Bo; Zhang, Xiao-Yun; Liu, Li-Zhi; Chen, Zhao-Hui; Dai, Zhong-Quan; Huang, Xu-Sheng

    2017-01-01

    Background: Few studies have focused on peripheral nerve conduction during exposure to microgravity. The −6° head-down tilt (HDT) comprises an experimental model used to simulate the space flight environment. This study investigated nerve conduction characteristics of rhesus monkeys before and after prolonged exposure to HDT. Methods: Six rhesus monkeys (3–4 years old) were tilted backward 6° from the horizontal. Nerve conduction studies (NCSs) were performed on the median, ulnar, tibial, and fibular motor nerves. Analysis of variance with a randomized block design was conducted to compare the differences in the NCS before and 7, 21, and 42 days after the −6° HDT. Results: The proximal amplitude of the CMAP of the median nerve was significantly decreased at 21 and 42 days of HDT compared with the amplitude before HDT (4.38 ± 2.83 vs. 8.40 ± 2.66 mV, F = 4.85, P = 0.013 and 3.30 ± 2.70 vs. 8.40 ± 2.66 mV, F = 5.93, P = 0.004, respectively). The distal amplitude of the CMAP of the median nerve was significantly decreased at 7, 21, and 42 days of HDT compared with the amplitude before HDT (7.28 ± 1.27 vs. 10.25 ± 3.40 mV, F = 4.03, P = 0.039; 5.05 ± 2.01 vs. 10.25 ± 3.40 mV, F = 6.25, P = 0.04; and 3.95 ± 2.79 vs. 10.25 ± 3.40 mV, F = 7.35, P = 0.01; respectively). The proximal amplitude of the CMAP of the tibial nerve was significantly decreased at 42 days of HDT compared with the amplitude before HDT (6.14 ± 1.94 vs. 11.87 ± 3.19 mV, F = 5.02, P = 0.039). Conclusions: This study demonstrates that the compound muscle action potential amplitudes of nerves are decreased under simulated microgravity in rhesus monkeys. Moreover, rhesus monkeys exposed to HDT might be served as an experimental model for the study of NCS under microgravity. PMID:28139516

  1. Therapeutic effectiveness of epicranial nerve blocks on post-traumatic syndrome from head injury

    Directory of Open Access Journals (Sweden)

    C. A. Caputi

    2011-03-01

    Full Text Available The autor describes the case of a 53-year-old woman suffering from headache and dizziness, sometimes nausea, tinnitus in the right ear, and diffuse scalp allodynia following an occupational accident involving a head injury. Hyposensitizing treatment by anesthetic blockade at the emergence points of the epicranial nerves, which were hyperalgesic to fi nger pressure, rapidly controlled the allodynia and eventually the headache. Unexpectedly, the patient also reported reduced dizziness and resolution of the tinnitus. The unforeseen outcome highlights the unpredictable therapeutic potential of a simple and modestly invasive procedure. The neuropathophysiological interpretation is consequently very interesting.

  2. Acellular allogeneic nerve grafting combined with bone marrow mesenchymal stem cell transplantation for the repair of long-segment sciatic nerve defects: biomechanics and validation of mathematical models

    Directory of Open Access Journals (Sweden)

    Ya-jun Li

    2016-01-01

    Full Text Available We hypothesized that a chemically extracted acellular allogeneic nerve graft used in combination with bone marrow mesenchymal stem cell transplantation would be an effective treatment for long-segment sciatic nerve defects. To test this, we established rabbit models of 30 mm sciatic nerve defects, and treated them using either an autograft or a chemically decellularized allogeneic nerve graft with or without simultaneous transplantation of bone marrow mesenchymal stem cells. We compared the tensile properties, electrophysiological function and morphology of the damaged nerve in each group. Sciatic nerves repaired by the allogeneic nerve graft combined with stem cell transplantation showed better recovery than those repaired by the acellular allogeneic nerve graft alone, and produced similar results to those observed with the autograft. These findings confirm that a chemically extracted acellular allogeneic nerve graft combined with transplantation of bone marrow mesenchymal stem cells is an effective method of repairing long-segment sciatic nerve defects.

  3. Malignant Peripheral Nerve Sheath Tumors of the Head and Neck: A Case Series and Literature Review

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    Brandon T. Mullins

    2014-01-01

    Full Text Available Background. Malignant peripheral nerve sheath tumors (MPNSTs of the head and neck are rare aggressive neoplasms with a poor prognosis. This study describes the management and outcomes of 3 of our patients with MPNSTs of the head and neck. Methods. We identified 3 patients presenting with MPNST of the head and neck and treated at the University of North Carolina. We compared our results to the literature from 1963 to 2014. Results. Mean follow-up was 31 months. Average age at diagnosis was 44.7 years of age. All patients received wide-local excision and adjuvant radiotherapy. No patients recurred during the series. Recurrence-free survival time for the patients was 45, 37, and 3 months, respectively. Conclusions. Our data series confirms that a combined-modality approach with complete surgical resection and adjuvant radiotherapy leads to improved outcomes in MPNSTs of the head and neck. Nonetheless, due to historically poor outcomes, continued research into newer therapies needs to be explored.

  4. Bilateral choroidal neovascularization associated with optic nerve head drusen treated by antivascular endothelial growth factor therapy

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    Carreras A

    2012-02-01

    Full Text Available Barbara Delas, Lorena Almudí, Anabel Carreras, Mouafk AsaadOphthalmology Service, Hospital de Terrassa, Barcelona, SpainObjective: To report a good clinical outcome in a patient with bilateral choroidal neovascularization (CNV associated with optic nerve head drusen (ONHD treated with intravitreal ranibizumab injection.Methods: A 12-year-old girl was referred for loss of right eye vision detected in a routine check-up. Best-corrected visual acuity (BCVA was hand movements in the right eye and 0.9 in the left eye. Funduscopy revealed the presence of superficial and buried bilateral ONHD, which was confirmed by ultrasonography and computed tomography, and the study was completed with perimetry. The presence of bilateral CNV, active in the right eye, was observed and subsequently confirmed using fluorescein angiography and optical coherence tomography.Results: Treatment with two consecutive injections of intravitreal ranibizumab resulted in inactivation of the neovascular membrane with subretinal fluid reabsorption and improved right eye BCVA. After 12 months’ follow-up, this was 20/60 and stable.Conclusion: Although there are no published studies of safety in children, antiangiogenic therapy for CNV secondary to ONHD may be useful and safe. A search of the literature produced only one previously reported case of ONHD-associated CNV treated with antivascular endothelial growth factor alone.Keywords: optic nerve head drusen, anti-vegf, children, neovascularisation

  5. The Effect of Education on the Assessment of Optic Nerve Head Photographs for the Glaucoma Diagnosis

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    Boehm Andreas G

    2011-05-01

    Full Text Available Abstract Background To evaluate the effect of one lesson of continuing medical education (CME of subjective assessment of optic nerve head appearance on sensitivity and specificity for the diagnosis of glaucoma. Methods Ophthalmologists and residents in ophthalmology attending an international glaucoma meeting arranged at Malmö University Hospital, Malmö, Sweden, were asked to grade optic nerve head (ONH photographs of healthy and glaucomatous subjects at two sessions separated by a lecture on glaucoma diagnosis by ONH assessment. Each grader had access to an individual portfolio of 50 ONH photographs randomly selected from a web-based data bank including ONH photographs of 73 glaucoma patients and 123 healthy subjects. The individual portfolio of photographs was graded before and after the lecture, but in different randomized order. Results Ninety-six doctors, 91% of all attending the meeting, completed both assessment sessions. The number of correct classifications increased from 69 to 72% on the average. Diagnostic sensitivity increased significantly (p Conclusion CME had only a small effect on the assessment of ONH for the glaucoma diagnosis. Sensitivity increased and the amount of uncertain classifications decreased, while specificity was unchanged.

  6. Biomechanical evaluation of the long head of the biceps brachii tendon fixed by three techniques: a sheep model

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    Carlos Henrique Ramos

    Full Text Available ABSTRACT OBJECTIVE: To evaluate the biomechanical properties of the fixation of the long head of the biceps brachii into the humeral bone with suture anchors, interference screw, and soft tissue suture, comparing strength, highest traction load, and types of fixation failure. METHODS: Thirty fresh-frozen sheep shoulders were used, separated into three groups of ten for each technique. After fixation, the tendons were subjected to longitudinal continuous loading, obtaining load-to-failure (N and displacement (mm. RESULTS: The mean load-to-failure for suture anchors was 95 ± 35.3 N, 152.7 ± 52.7 N for interference screw, and 104.7 ± 23.54 N for soft tissue technique. There was a statistically significant difference (p < 0.05, with interference screw demonstrating higher load-to-failure than suture anchor fixation (p = 0.00307 and soft tissue (p = 0.00473. The strength of interference screw was also superior when compared with the other two methods (p = 0.0000127 and p = 0.00000295, respectively. There were no differences between suture anchors and soft tissue technique regarding load-to-failure (p = 0.9420 and strength (p = 0.141. CONCLUSION: Tenodesis of the long head of the biceps brachii with interference screw was stronger than the suture anchors and soft tissue techniques. The other two techniques did not differ between themselves.

  7. Parametric analysis of the biomechanical response of head subjected to the primary blast loading--a data mining approach.

    Science.gov (United States)

    Zhu, Feng; Kalra, Anil; Saif, Tal; Yang, Zaihan; Yang, King H; King, Albert I

    2016-01-01

    Traumatic brain injury due to primary blast loading has become a signature injury in recent military conflicts and terrorist activities. Extensive experimental and computational investigations have been conducted to study the interrelationships between intracranial pressure response and intrinsic or 'input' parameters such as the head geometry and loading conditions. However, these relationships are very complicated and are usually implicit and 'hidden' in a large amount of simulation/test data. In this study, a data mining method is proposed to explore such underlying information from the numerical simulation results. The heads of different species are described as a highly simplified two-part (skull and brain) finite element model with varying geometric parameters. The parameters considered include peak incident pressure, skull thickness, brain radius and snout length. Their interrelationship and coupling effect are discovered by developing a decision tree based on the large simulation data-set. The results show that the proposed data-driven method is superior to the conventional linear regression method and is comparable to the nonlinear regression method. Considering its capability of exploring implicit information and the relatively simple relationships between response and input variables, the data mining method is considered to be a good tool for an in-depth understanding of the mechanisms of blast-induced brain injury. As a general method, this approach can also be applied to other nonlinear complex biomechanical systems.

  8. Differentiating Mild Papilledema and Buried Optic Nerve Head Drusen Using Spectral Domain Optical Coherence Tomography

    Science.gov (United States)

    Kulkarni, Kaushal M.; Pasol, Joshua; Rosa, Potyra R.; Lam, Byron L.

    2013-01-01

    Purpose To evaluate the clinical utility of spectral domain optical coherence tomography (SD-OCT) in differentiating mild papilledema from buried optic nerve head drusen (ONHD). Design Comparative case series. Participants 16 eyes of 9 patients with ultrasound-proven buried ONHD, 12 eyes of 6 patients with less than or equal to Frisén grade 2 papilledema due to idiopathic intracranial hypertension. 2 normal fellow eyes of patients with buried ONHD were included. Methods A raster scan on the optic nerve and retinal nerve fiber layer (RNFL) thickness analysis was performed on each eye using SD-OCT. Eight eyes underwent enhanced depth imaging SD-OCT. Images were assessed qualitatively and quantitatively to identify differentiating features between buried ONHD and papilledema. Five clinicians trained with a tutorial and masked to the underlying diagnosis reviewed the SD-OCT images of each eye independently to determine the diagnosis. Main outcome measures Differences in RNFL thickness in each quadrant between the two groups, and diagnostic accuracy of five independent clinicians based on the SD-OCT images alone. Results We found no statistically significant difference in RNFL thickness between buried ONHD and papilledema in any of the four quadrants. Diagnostic accuracy among the readers was low and ranged from 50–64%. The kappa coefficient of agreement among the readers was 0.35 (95% Confidence interval: 0.19, 0.54). Conclusions SD-OCT is not clinically reliable in differentiating buried ONHD and mild papilledema. PMID:24321144

  9. Correlation between optic nerve head structural parameters and glaucomatous visual field indices.

    Science.gov (United States)

    Mizumoto, Kyoichi; Gosho, Masahiko; Zako, Masahiro

    2014-01-01

    We examined associations between optic nerve head structural parameters and glaucomatous visual field indices. The study population included patients with glaucomatous optic neuropathy who were evaluated at Aichi Medical University, Nagakute, Aichi, Japan, from October 2010 to January 2011. A total of 57 eyes from 33 patients were assessed. We measured visual field using a Humphrey field analyzer, peripapillary retinal nerve fiber layer thickness (RNFL-T), and Bruch's membrane opening-minimum rim width (BMO-MRW) using spectral domain optical coherence tomography, and rim area with referring three-dimensional photography. Spearman's rank correlation coefficients were calculated between the threshold of visual sensitivity or total deviation of visual field and the following five optic nerve head structural parameters: RNFL-T length, BMO-MRW length, rim area, and calculated RNFL-T and BMO-MRW volumes (each length multiplied by rim area). The Akaike information criterion was calculated to determine which structural parameter was the best predictor of each visual field index. Threshold of visual sensitivity had correlation coefficients of 0.23 with global sector of RNFL-T, 0.32 with BMO-MRW, 0.14 with rim area, 0.21 with RNFL-T volume, and 0.26 with BMO-MRW volume. The correlation coefficients for each parameter with total deviation of visual field were 0.22, 0.33, 0.28, 0.36, and 0.37, respectively. The Akaike information criterion of BMO-MRW showed the smallest values in analyses of both threshold of visual sensitivity and total deviation. The present results show that RNFL-T volume and BMO-MRW volume were more strongly correlated with total deviation than BMO-MRW, but BMO-MRW appeared to be the best predictor of the two glaucomatous visual field indices.

  10. Biomechanical head impact characteristics during sparring practice sessions in high school taekwondo athletes.

    Science.gov (United States)

    O'Sullivan, David M; Fife, Gabriel P

    2017-06-01

    OBJECTIVE The purpose of this study was to monitor head impact magnitude and characteristics, such as impact location and frequency, at high school taekwondo sparring sessions. METHODS Eight male high school taekwondo athletes participated in this study. The head impact characteristics were recorded by X-Patch, a wireless accelerometer and gyroscope, during 6 taekwondo sparring sessions. The outcome measures were the peak linear acceleration ( g = 9.81 msec(2)), peak rotational acceleration, rotational velocity, and Head Injury Criterion. RESULTS A total of 689 impacts occurred over 6 sessions involving the 8 athletes. There was an average of 24 impacts per 100 minutes, and there were significant differences in the frequency of impacts among both the sessions and individual athletes. In order of frequency, the most commonly hit locations were the side (38.2%), back (35.7%), and front (23.8%) of the head. CONCLUSIONS The data indicate that there is a relatively high number of head impacts experienced by taekwondo athletes during sparring practice. According to the rotational acceleration predicting impact severity published in previous research, 17.1% of the impacts were deemed to be a moderate and 15.5% were deemed to be severe.

  11. A GPU based high-resolution multilevel biomechanical head and neck model for validating deformable image registration

    Energy Technology Data Exchange (ETDEWEB)

    Neylon, J., E-mail: jneylon@mednet.ucla.edu; Qi, X.; Sheng, K.; Low, D. A.; Kupelian, P.; Santhanam, A. [Department of Radiation Oncology, University of California Los Angeles, 200 Medical Plaza, #B265, Los Angeles, California 90095 (United States); Staton, R.; Pukala, J.; Manon, R. [Department of Radiation Oncology, M.D. Anderson Cancer Center, Orlando, 1440 South Orange Avenue, Orlando, Florida 32808 (United States)

    2015-01-15

    Purpose: Validating the usage of deformable image registration (DIR) for daily patient positioning is critical for adaptive radiotherapy (RT) applications pertaining to head and neck (HN) radiotherapy. The authors present a methodology for generating biomechanically realistic ground-truth data for validating DIR algorithms for HN anatomy by (a) developing a high-resolution deformable biomechanical HN model from a planning CT, (b) simulating deformations for a range of interfraction posture changes and physiological regression, and (c) generating subsequent CT images representing the deformed anatomy. Methods: The biomechanical model was developed using HN kVCT datasets and the corresponding structure contours. The voxels inside a given 3D contour boundary were clustered using a graphics processing unit (GPU) based algorithm that accounted for inconsistencies and gaps in the boundary to form a volumetric structure. While the bony anatomy was modeled as rigid body, the muscle and soft tissue structures were modeled as mass–spring-damper models with elastic material properties that corresponded to the underlying contoured anatomies. Within a given muscle structure, the voxels were classified using a uniform grid and a normalized mass was assigned to each voxel based on its Hounsfield number. The soft tissue deformation for a given skeletal actuation was performed using an implicit Euler integration with each iteration split into two substeps: one for the muscle structures and the other for the remaining soft tissues. Posture changes were simulated by articulating the skeletal structure and enabling the soft structures to deform accordingly. Physiological changes representing tumor regression were simulated by reducing the target volume and enabling the surrounding soft structures to deform accordingly. Finally, the authors also discuss a new approach to generate kVCT images representing the deformed anatomy that accounts for gaps and antialiasing artifacts that may

  12. Safe-Play Knowledge, Aggression, and Head-Impact Biomechanics in Adolescent Ice Hockey Players.

    Science.gov (United States)

    Schmidt, Julianne D; Pierce, Alice F; Guskiewicz, Kevin M; Register-Mihalik, Johna K; Pamukoff, Derek N; Mihalik, Jason P

    2016-05-01

    Addressing safe-play knowledge and player aggression could potentially improve ice hockey sport safety. To compare (1) safe-play knowledge and aggression between male and female adolescent ice hockey players and (2) head-impact frequency and severity between players with high and low levels of safe-play knowledge and aggression during practices and games. Cohort study. On field. Forty-one male (n = 29) and female (n = 12) adolescent ice hockey players. Players completed the Safe Play Questionnaire (0 = less knowledge, 7 = most knowledge) and Competitive Aggressiveness and Anger Scale (12 = less aggressive, 60 = most aggressive) at midseason. Aggressive penalty minutes were recorded throughout the season. The Head Impact Telemetry System was used to capture head-impact frequency and severity (linear acceleration [g], rotational acceleration [rad/s(2)], Head Impact Technology severity profile) at practices and games. One-way analyses of variance were used to compare safe play knowledge and aggression between sexes. Players were categorized as having high or low safe-play knowledge and aggression using a median split. A 2 × 2 mixed-model analysis of variance was used to compare head-impact frequency, and random-intercept general linear models were used to compare head-impact severity between groups (high, low) and event types (practice, game). Boys (5.8 of 7 total; 95% confidence interval [CI] = 5.3, 6.3) had a trend toward better safe-play knowledge compared with girls (4.9 of 7 total; 95% CI = 3.9, 5.9; F1,36 = 3.40, P = .073). Less aggressive male players sustained significantly lower head rotational accelerations during practices (1512.8 rad/s (2) , 95% CI = 1397.3, 1637.6 rad/s(2)) versus games (1754.8 rad/s (2) , 95% CI = 1623.9, 1896.2 rad/s(2)) and versus high-aggression players during practices (1773.5 rad/s (2) , 95% CI = 1607.9, 1956.3 rad/s (2) ; F1,26 = 6.04, P = .021). Coaches and sports medicine professionals should ensure that athletes of all levels

  13. Changes in quantitative 3D shape features of the optic nerve head associated with age

    Science.gov (United States)

    Christopher, Mark; Tang, Li; Fingert, John H.; Scheetz, Todd E.; Abramoff, Michael D.

    2013-02-01

    Optic nerve head (ONH) structure is an important biological feature of the eye used by clinicians to diagnose and monitor progression of diseases such as glaucoma. ONH structure is commonly examined using stereo fundus imaging or optical coherence tomography. Stereo fundus imaging provides stereo views of the ONH that retain 3D information useful for characterizing structure. In order to quantify 3D ONH structure, we applied a stereo correspondence algorithm to a set of stereo fundus images. Using these quantitative 3D ONH structure measurements, eigen structures were derived using principal component analysis from stereo images of 565 subjects from the Ocular Hypertension Treatment Study (OHTS). To evaluate the usefulness of the eigen structures, we explored associations with the demographic variables age, gender, and race. Using regression analysis, the eigen structures were found to have significant (p glaucoma, disease progression and outcomes, and genetic factors.

  14. Laser Doppler measurement of relative blood velocity in the human optic nerve head.

    Science.gov (United States)

    Riva, C E; Grunwald, J E; Sinclair, S H

    1982-02-01

    The Doppler shift frequency spectrum (DSFS) of laser light scattered from red blood cells (RBCs) moving in the microcirculation of the optic nerve head has been recorded in normal volunteers by means of a fundus camera laser Doppler velocimeter. The width of the DSFS, which varies in proportion to the speed of the RBCs, has been characterized by a parameter alpha. With the use of a model for the scattering of light by tissue and RBCs and for the RBC velocity distribution, values of alpha recorded at normal intraocular pressure (IOP) suggest that the RBCs that contribute to the Doppler signal are flowing in capillaries. The parameter alpha was found to vary markedly with the IOP and with the phase of the ocular pressure pulse at elevated IOP. The return of the speed of RBCs toward normal, which is observed after a step increase of IOP above normal and after a step decrease below normal, has been attributed to an autoregulatory response of the optic nerve circulation.

  15. Scanning laser topography and scanning laser polarimetry: comparing both imaging methods at same distances from the optic nerve head.

    Science.gov (United States)

    Kremmer, Stephan; Keienburg, Marcus; Anastassiou, Gerasimos; Schallenberg, Maurice; Steuhl, Klaus-Peter; Selbach, J Michael

    2012-01-01

    To compare the performance of scanning laser topography (SLT) and scanning laser polarimetry (SLP) on the rim of the optic nerve head and its surrounding area and thereby to evaluate whether these imaging technologies are influenced by other factors beyond the thickness of the retinal nerve fiber layer (RNFL). A total of 154 eyes from 5 different groups were examined: young healthy subjects (YNorm), old healthy subjects (ONorm), patients with normal tension glaucoma (NTG), patients with open-angle glaucoma and early glaucomatous damage (OAGE) and patients with open-angle glaucoma and advanced glaucomatous damage (OAGA). SLT and SLP measurements were taken. Four concentric circles were superimposed on each of the images: the first one measuring at the rim of the optic nerve head (1.0 ONHD), the next measuring at 1.25 optic nerve head diameters (ONHD), at 1.5 ONHD and at 1.75 ONHD. The aligned images were analyzed using GDx/NFA software. Both methods showed peaks of RNFL thickness in the superior and inferior segments of the ONH. The maximum thickness, registered by the SLT device was at the ONH rim where the SLP device tended to measure the lowest values. SLT measurements at the ONH were influenced by other tissues besides the RNFL like blood vessels and glial tissues. SLT and SLP were most strongly correlated at distances of 1.25 and 1.5 ONHD. While both imaging technologies are valuable tools in detecting glaucoma, measurements at the ONH rim should be interpreted critically since both methods might provide misleading results. For the assessment of the retinal nerve fiber layer we would like to recommend for both imaging technologies, SLT and SLP, measurements in 1.25 and 1.5 ONHD distance of the rim of the optic nerve head.

  16. Head and neck injury patterns in fatal falls: epidemiologic and biomechanical considerations.

    Science.gov (United States)

    Freeman, Michael D; Eriksson, Anders; Leith, Wendy

    2014-01-01

    Fatal falls often involve a head impact, which are in turn associated with a fracture of the skull or cervical spine. Prior authors have noted that the degree of inversion of the victim at the time of impact is an important predictor of the distribution of skull fractures, with skull base fractures more common than skull vault fractures in falls with a high degree of inversion. The majority of fatal fall publications have focused on skull fractures, and no research has described the association between fall circumstances and the distribution of fractures in the skull and neck. In the present study, we accessed data regarding head and neck fractures resulting from fatal falls from a Swedish autopsy database for the years 1992-2010, for the purposes of examining the relationships between skull and cervical spine fracture distribution and the circumstances of the fatal fall. Out of 102,310 medico-legal autopsies performed there were 1008 cases of falls associated with skull or cervical spine fractures. The circumstances of the falls were grouped in 3 statistically homogenous categories; falls occurring at ground level, falls from a height of cervical injuries (C0-C1 dislocation, C1 and C2 fractures), and lower cervical fractures. Logistic regression modeling revealed increased odds of skull base and lower cervical fracture in the middle and upper fall severity groups, relative to ground level falls (lower cervical cervical ≥3 m falls, OR = 2.23 [0.98, 5.08]; skull base cervical spine fracture in falls from a height are consistent with prior observations that the risk of such injuries is related to the degree of victim inversion at impact. The finding that C0-C1 dislocations are most common in falls from more than 3 m is unique, an indication that the injuries likely result from high energy shear forces rather than pure tension, as previously thought.

  17. Impact of order of movement on nerve strain and longitudinal excursion: a biomechanical study with implications for neurodynamic test sequencing.

    Science.gov (United States)

    Nee, Robert J; Yang, Chich-Haung; Liang, Chung-Chao; Tseng, Guo-Fang; Coppieters, Michel W

    2010-08-01

    It is assumed that strain in a nerve segment at the end of a neurodynamic test will be greatest if the joint nearest that nerve segment is moved first in the neurodynamic test sequence. To test this assumption, the main movements of the median nerve biased neurodynamic test were applied in three different sequences to seven fresh-frozen human cadavers. Strain and longitudinal excursion were measured in the median nerve at the distal forearm. Strain and relative position of the nerve at the end of a test did not differ between sequences. The nerve was subjected to higher levels of strain for a longer duration during the sequence where wrist extension occurred first. The pattern of excursion was different for each sequence. The results highlight that order of movement does not affect strain or relative position of the nerve at the end of a test when joints are moved through comparable ranges of motion. When used clinically, different neurodynamic sequences may still change the mechanical load applied to a nerve segment. Changes in load may occur because certain sequences apply increased levels of strain to the nerve for a longer time period, or because sequences differ in ranges of joint motions.

  18. The Trigeminal (V) and Facial (VII) Cranial Nerves: Head and Face Sensation and Movement

    OpenAIRE

    Sanders, Richard D.

    2010-01-01

    There are close functional and anatomical relationships between cranial nerves V and VII in both their sensory and motor divisions. Sensation on the face is innervated by the trigeminal nerves (V) as are the muscles of mastication, but the muscles of facial expression are innervated mainly by the facial nerve (VII) as is the sensation of taste. This article briefly reviews the anatomy of these cranial nerves, disorders of these nerves that are of particular importance to psychiatry, and some ...

  19. Measuring Deformation in the Mouse Optic Nerve Head and Peripapillary Sclera

    Science.gov (United States)

    Nguyen, Cathy; Midgett, Dan; Kimball, Elizabeth C.; Steinhart, Matthew R.; Nguyen, Thao D.; Pease, Mary E.; Oglesby, Ericka N.; Jefferys, Joan L.; Quigley, Harry A.

    2017-01-01

    Purpose To develop an ex vivo explant system using multiphoton microscopy and digital volume correlation to measure the full-field deformation response to intraocular pressure (IOP) change in the peripapillary sclera (PPS) and in the optic nerve head (ONH) astrocytic structure. Methods Green fluorescent protein (GFP)-glutamate transporter-GLT1 (GLT1/GFP) mouse eyes were explanted and imaged with a laser-scanning microscope under controlled inflation. Images were analyzed for regional strains and changes in astrocytic lamina and PPS shape. Astrocyte volume fraction in seven control GLT1/GFP mice was measured. The level of fluorescence of GFP fluorescent astrocytes was compared with glial fibrillary acidic protein (GFAP) labeled astrocytes using immunohistochemistry. Results The ONH astrocytic structure remained stable during 3 hours in explants. Control strain—globally, in the central one-half or two-thirds of the astrocytic lamina—was significantly greater in the nasal-temporal direction than in the inferior-superior or anterior-posterior directions (each P ≤ 0.03, mixed models). The PPS opening (perimeter) in normal eye explants also became wider nasal-temporally than superior-inferiorly during inflation from 10 to 30 mm Hg (P = 0.0005). After 1 to 3 days of chronic IOP elevation, PPS area was larger than in control eyes (P = 0.035), perimeter elongation was 37% less than controls, and global nasal-temporal strain was significantly less than controls (P = 0.007). Astrocyte orientation was altered by chronic IOP elevation, with processes redirected toward the longitudinal axis of the optic nerve. Conclusions The explant inflation test measures the strain response of the mouse ONH to applied IOP. Initial studies indicate regional differences in response to both acute and chronic IOP elevation within the ONH region. PMID:28146237

  20. In Vivo Changes in Lamina Cribrosa Microarchitecture and Optic Nerve Head Structure in Early Experimental Glaucoma.

    Directory of Open Access Journals (Sweden)

    Kevin M Ivers

    Full Text Available The lamina cribrosa likely plays an important role in retinal ganglion cell axon injury in glaucoma. We sought to (1 better understand optic nerve head (ONH structure and anterior lamina cribrosa surface (ALCS microarchitecture between fellow eyes of living, normal non-human primates and (2 characterize the time-course of in vivo structural changes in the ONH, ALCS microarchitecture, and retinal nerve fiber layer thickness (RNFLT in non-human primate eyes with early experimental glaucoma (EG. Spectral domain optical coherence tomography (SDOCT images of the ONH were acquired cross-sectionally in six bilaterally normal rhesus monkeys, and before and approximately every two weeks after inducing unilateral EG in seven rhesus monkeys. ONH parameters and RNFLT were quantified from segmented SDOCT images. Mean ALCS pore area, elongation and nearest neighbor distance (NND were quantified globally, in sectors and regionally from adaptive optics scanning laser ophthalmoscope images. In bilaterally normal monkeys, ONH parameters were similar between fellow eyes with few inter-eye differences in ALCS pore parameters. In EG monkeys, an increase in mean ALCS Depth (ALCSD was the first structural change measured in 6 of 7 EG eyes. A decrease in mean minimum rim width (MRW simultaneously accompanied this early change in 4 of 6 EG eyes and was the first structural change in the 7th EG eye. Mean ALCS pore parameters were among the first or second changes measured in 4 EG eyes. Mean ALCS pore area and NND increased in superotemporal and temporal sectors and in central and peripheral regions at the first time-point of change in ALCS pore geometry. RNFLT and/or mean ALCS radius of curvature were typically the last parameters to initially change. Survival analyses found mean ALCSD was the only parameter to significantly show an initial change prior to the first measured loss in RNFLT across EG eyes.

  1. Optical coherence tomography in papilledema and pseudopapilledema with and without optic nerve head drusen

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    Shikha Talwar Bassi

    2014-01-01

    Full Text Available Aim: To compare the spectral domain optical coherence tomography (SD-OCT findings of the optic disc and the peripapillary retina of patients with a true papilledema and pseudopapilledema with and without optic nerve head drusen (ONHD. Study Design: Retrospective Case Control Study. Subjects and Methods: Peripapillary retinal nerve fiber layer (PPRNFL thickness as depicted by SD-OCT of 94 eyes of 66 patients with papilledema (30 eyes, pseudopapiledema (31 eyes, and normal controls (33 eyes was analyzed. The mean RNFL thickness, total retinal thickness (TRT at a superior and inferior edge of the disc and the quadrant wise topography of increased RNFL were compared in all three groups. Sensitivity, specificity, and area under the receiver operating characteristic curve (AROC were calculated for all the parameters. Results: The median RNFL thickness was 185.4 (129.5-349.3 μm, 122.3 (109-156.3 μm and 91.62 ± 7 μm in papilledema, pseudopapilledema, and controls, respectively. Papilledema group had thicker PPRNFL in all quadrants except temporal quadrant. TRT was thicker in papilledema and pseudopapilledema compared to controls. ONHD could be directly visualized as high reflective clumps in the sub-retinal space or the RNFL in 30 eyes. Increased RNFL thickness in all four quadrants was noted 43.3% in papilledema and 9.7% in pseudopapilledema. Normal RNFL thickness in all four quadrants was noted in 0% in papilledema and 32.3% in pseudopapilledema. Nasal RNFL had the highest AROC (0.792 indicating high diagnostic ability to differentiate papilledema from pseudopapilledema. Conclusion: SD-OCT can be used as a tool to differentiate between papilledema and pseudopapilledema.

  2. Gender- and Ethnicity-Related Differences in Optic Nerve Head Topography in Healthy Indian and Caucasian Participants.

    Science.gov (United States)

    Pilat, Anastasia V; Gottlob, Irene; Sheth, Viral; Thomas, Mervyn G; Proudlock, Frank A

    2014-01-01

    We investigated the effect of ethnicity and gender on optic nerve head morphology in healthy subjects using spectral-domain optical coherence tomography (SD-OCT). Thirty-five Indian (i.e. Indian subcontinent) females, 34 Caucasian females, 32 Indian males, and 32 Caucasian males were examined using SD-OCT (Copernicus, Optopol Technology). Disc and rim areas were larger in Caucasian males compared with females but smaller in Indians males compared with females. Indian participants had significantly larger cup areas and volumes without significant differences in retinal nerve fibre layer (RNFL) thicknesses between groups. Gender and ethnicity differences should be considered in assessment of patients.

  3. Influence of automated disc margin determination on Stratus OCT optic nerve head measurements

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    Soares de Camargo A

    2014-03-01

    Full Text Available André Soares de Camargo, Luiz Alberto Soares Melo Jr, Flavio Eduardo Hirai, Ivan Maynart Tavares Glaucoma Service, Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, Paulista Medical School, São Paulo, Brazil Purpose: To analyze the influence of manual correction of the automatically determined edge of the optic nerve head (ONH in optic disc measurements in cases in which the optical coherence tomography did not identify the disc limits correctly. Methods: The study included 127 eyes from 127 consecutive patients with glaucoma, suspects, and healthy individuals. In a retrospective analysis, eyes that underwent testing with the Stratus OCT (software version 4.0, Carl Zeiss Meditec, Dublin, CA, USA Fast Optic Disc protocol were evaluated. Forty-seven eyes in which either the manual assignment was not necessary or the signal strength was below six were excluded. After image acquisition and processing, one expert examiner manually corrected the determination of the edge of the ONH, identified as the end of the retinal pigment epithelium/choriocapillaris complex. Disc area, cup area, rim area, and cup/disc area ratio results were compared before and after the optic disc margin manually corrected determination. Paired t-test was performed to evaluate the differences, and Bland–Altman plots were used to display the relationships between measurements. Results: Eighty eyes from 80 individuals were included in the analyses. No statistically significant difference (P=0.538 was found when analyzing results obtained with automated and manual determination of rim area (mean ± standard deviation; 1.30±0.45 mm2 and 1.29±0.39 mm2, respectively. Cup area (1.39±0.58 mm2 and 1.31±0.55 mm2, respectively, cup/disc area ratio (0.50±0.16 mm2 and 0.49±0.15 mm2, respectively, and disc area results (2.69±0.55 mm2 and 2.60±0.51 mm2, respectively were significantly different. Conclusion: The Stratus OCT ONH Report results were

  4. Natural motion of the optic nerve head revealed by high speed phase-sensitive OCT

    Science.gov (United States)

    OHara, Keith; Schmoll, Tilman; Vass, Clemens; Leitgeb, Rainer A.

    2013-03-01

    We use phase-sensitive optical coherence tomography (OCT) to measure the deformation of the optic nerve head during the pulse cycle, motivated by the possibility that these deformations might be indicative of the progression of glaucoma. A spectral-domain OCT system acquired 100k A-scans per second, with measurements from a pulse-oximeter recorded simultaneously, correlating OCT data to the subject's pulse. Data acquisition lasted for 2 seconds, to cover at least two pulse cycles. A frame-rate of 200-400 B-scans per second results in a sufficient degree of correlated speckle between successive frames that the phase-differences between fames can be extracted. Bulk motion of the entire eye changes the phase by several full cycles between frames, but this does not severely hinder extracting the smaller phase-changes due to differential motion within a frame. The central cup moves about 5 μm/s relative to the retinal-pigment-epithelium edge, with tissue adjacent to blood vessels showing larger motion.

  5. Repeatability and reproducibility of optic nerve head perfusion measurements using optical coherence tomography angiography

    Science.gov (United States)

    Chen, Chieh-Li; Bojikian, Karine D.; Xin, Chen; Wen, Joanne C.; Gupta, Divakar; Zhang, Qinqin; Mudumbai, Raghu C.; Johnstone, Murray A.; Chen, Philip P.; Wang, Ruikang K.

    2016-06-01

    Optical coherence tomography angiography (OCTA) has increasingly become a clinically useful technique in ophthalmic imaging. We evaluate the repeatability and reproducibility of blood perfusion in the optic nerve head (ONH) measured using optical microangiography (OMAG)-based OCTA. Ten eyes from 10 healthy volunteers are recruited and scanned three times with a 68-kHz Cirrus HD-OCT 5000-based OMAG prototype system (Carl Zeiss Meditec Inc., Dublin, California) centered at the ONH involving two separate visits within six weeks. Vascular images are generated with OMAG processing by detecting the differences in OCT signals between consecutive B-scans acquired at the same retina location. ONH perfusion is quantified as flux, vessel area density, and normalized flux within the ONH for the prelaminar, lamina cribrosa, and the full ONH. Coefficient of variation (CV) and intraclass correlation coefficient (ICC) are used to evaluate intravisit and intervisit repeatability, and interobserver reproducibility. ONH perfusion measurements show high repeatability [CV≤3.7% (intravisit) and ≤5.2% (intervisit)] and interobserver reproducibility (ICC≤0.966) in all three layers by three metrics. OCTA provides a noninvasive method to visualize and quantify ONH perfusion in human eyes with excellent repeatability and reproducibility, which may add additional insight into ONH perfusion in clinical practice.

  6. The connective tissue and glial framework in the optic nerve head of the normal human eye: light and scanning electron microscopic studies.

    Science.gov (United States)

    Oyama, Tokuhide; Abe, Haruki; Ushiki, Tatsuo

    2006-12-01

    The arrangement of connective tissue components (i.e., collagen, reticular, and elastic fibers) and glial elements in the optic nerve head of the human eye was investigated by the combined use of light microscopy and scanning electron microscopy (SEM). Light-microscopically, the optic nerve head could be subdivided into four parts from the different arrangements of the connective tissue framework: a surface nerve fiber layer, and prelaminar, laminar, and postlaminar regions. The surface nerve fiber layer only possessed connective tissue elements around blood vessels. In the prelaminar region, collagen fibrils, together with delicate elastic fibers, formed thin interrupted sheaths for accommodating small nerve bundles. Immunohistochemistry for the glial fibrillary acidic protein (GFAP) showed that GFAP-positive cells formed columnar structures (i.e., glial columns), with round cell bodies piled up into layers. These glial columns were located in the fibrous sheaths of collagen fibrils and elastic fibers. In the laminar region, collagen fibrils and elastic fibers ran transversely to the optic nerve axis to form a thick membranous layer - the lamina cribrosa - which had numerous round openings for accommodating optic nerve fiber bundles. GFAP-positive cellular processes also ran transversely in association with collagen and elastin components. The postlaminar region had connective tissues which linked the lamina cribrosa with fibrous sheaths for accommodating nerve bundles in the extraocular optic nerve, where GFAP-positive cells acquired characteristics typical of fibrous astrocytes. These findings indicate that collagen fibrils, as a whole, form a continuous network which serves as a skeletal framework of the optic nerve head for protecting optic nerve fibers from mechanical stress as well as for sustaining blood vessels in the optic nerve. The lamina cribrosa containing elastic fibers are considered to be plastic against the mechanical force affected by elevation

  7. Optic nerve head and intraocular pressure in the guinea pig eye.

    Science.gov (United States)

    Ostrin, Lisa A; Wildsoet, Christine F

    2016-05-01

    The guinea pig is becoming an increasingly popular model for studying human myopia, which carries an increased risk of glaucoma. As a step towards understanding this association, this study sought to characterize the normal, developmental intraocular pressure (IOP) profiles, as well as the anatomy of the optic nerve head (ONH) and adjacent sclera of young guinea pigs. IOP was tracked in pigmented guinea pigs up to 3 months of age. One guinea pig was imaged in vivo with OCT and one with a fundus camera. The eyes of pigmented and albino guinea pigs (ages 2 months) were enucleated and sections from the posterior segment, including the ONH and surrounding sclera, processed for histological analyses - either hematoxylin and eosin (H&E) staining of paraffin embedded, sectioned tissue (n = 1), or cryostat sectioned tissue, processed for immunohistochemistry (n = 3), using primary antibodies against collagen types I-V, elastin, fibronectin and glial fibrillary acidic protein (GFAP). Transmission and scanning electron microscopy (TEM, SEM) studies of ONHs were also undertaken (n = 2 & 5 respectively). Mean IOPs ranged from 17.33 to 22.7 mmHg, increasing slightly across the age range studied, and the IOPs of individual animals also exhibited diurnal variations, peaking in the early morning (mean of 25.8, mmHg, ∼9 am), and decreasing across the day. H&E-stained sections showed retinal ganglion cell axons organized into fascicles in the prelaminar and laminar region of the ONHs, with immunostained sections revealing collagen types I, III, IV and V, as well as elastin, GFAP and fibronectin in the ONHs. SEM revealed a well-defined lamina cribrosa (LC), with radially-oriented collagen beams. TEM revealed collagen fibrils surrounding non-myelinated nerve fiber bundles in the LC region, with myelination and decreased collagen posterior to the LC. The adjacent sclera comprised mainly crimped collagen fibers in a crisscross arrangement. Both the sclera and LC were

  8. Radical pancreatoduodenectomy combined with retroperitoneal nerve,lymph,and soft-tissue dissection in pancreatic head cancer

    Institute of Scientific and Technical Information of China (English)

    SHAO Qin-shu; YE Zai-yuan; LI Shu-guang; CHEN Kan

    2008-01-01

    Background Recent studies have revealed that the reason for the low surgical resection rate of pancreatic carcinoma partly lies in its biological behavior,which is characterized by neural infiltration.This study aimed to investigate the clinical significance of radical pancreatOduodenectomy combined with retroperitoneal nerve,lymph,and soft-tissue dissection for carcinoma of the pancreatic head.Methods Forty-six patients with pancreatic head cancer were treated in our hospital from 1995 to 2005.The patients were divided into two groups:radical pancreatoduodenectomy combined with retroperitoneal nerve,lymph and soft-tissue dissection (group A,n=25) and routine Whipple's operation (group B,n=21).There were no significant differences between the two groups in relation to age,gender and preoperative risk factors,and perioperative conditions,pathological data and survival rates were studied.Results There were no significant differences in tumor size,surgical procedure time,postoperative complications,and time of hospitalization.However,the number and positive rate of resected lymph nodes in group A were significantly higher than those in group B (P<0.05).The 1-and 3-year survival rate in group A were 80% and 53%,respectively,which was higher than those in group B (P<0.05).There were significant differences in the survival rates between patients with and without nerve infiltration in group A (P<0.05).Conclusions Radical pancreatoduodenectomy combined with retroperitoneal nerve,lymph and soft-tissue dissection,can effectiveoly remove the lymph and nerve tissues that were infiltrated by tumor.Meanwhile,this method can reduce the local recurrence rate so as to improve the long-term survival of patients.

  9. On the vagal cardiac nerves, with special reference to the early evolution of the head-trunk interface.

    Science.gov (United States)

    Higashiyama, Hiroki; Hirasawa, Tatsuya; Oisi, Yasuhiro; Sugahara, Fumiaki; Hyodo, Susumu; Kanai, Yoshiakira; Kuratani, Shigeru

    2016-09-01

    The vagus nerve, or the tenth cranial nerve, innervates the heart in addition to other visceral organs, including the posterior visceral arches. In amniotes, the anterior and posterior cardiac branches arise from the branchial and intestinal portions of the vagus nerve to innervate the arterial and venous poles of the heart, respectively. The evolution of this innervation pattern has yet to be elucidated, due mainly to the lack of morphological data on the vagus in basal vertebrates. To investigate this topic, we observed the vagus nerves of the lamprey (Lethenteron japonicum), elephant shark (Callorhinchus milii), and mouse (Mus musculus), focusing on the embryonic patterns of the vagal branches in the venous pole. In the lamprey, no vagus branch was found in the venous pole throughout development, whereas the arterial pole was innervated by a branch from the branchial portion. In contrast, the vagus innervated the arterial and venous poles in the mouse and elephant shark. Based on the morphological patterns of these branches, the venous vagal branches of the mouse and elephant shark appear to belong to the intestinal part of the vagus, implying that the cardiac nerve pattern is conserved among crown gnathostomes. Furthermore, we found a topographical shift of the structures adjacent to the venous pole (i.e., the hypoglossal nerve and pronephros) between the extant gnathostomes and lamprey. Phylogenetically, the lamprey morphology is likely to be the ancestral condition for vertebrates, suggesting that the evolution of the venous branch occurred early in the gnathostome lineage, in parallel with the remodeling of the head-trunk interfacial domain during the acquisition of the neck. J. Morphol. 277:1146-1158, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  10. Bilateral optic nerve head hemangioma in Von Hippel Lindau disease: Report of a case with severe visual loss

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    Abdollahi A

    2001-06-01

    Full Text Available A 22 year-old woman presented with gradual visual loss in her right eye since 1990. Medical and family histories were unremarkable. Her visual acuity was 20/80 and 20/20 in right and left eyes respectively. Slit lamp examination was quite normal with no relative afferent papillary defect.Fundi of both eyes revealed subretinal lesion with optic nerve head involvement and subretinal fluid in papillomacular bundle with macular pucker in right eye. Whole body MRI revealed a large hemangioma in the spinal canal. In 1998 the patient ahsd significant visual loss at both eyes. This is the first report of Von hippel disease with bilateral optic nerve hemangioma in Iran.

  11. Optic nerve head analysis of superior segmental optic hypoplasia using Heidelberg retina tomography

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    Atsushi Miki

    2010-10-01

    , especially in the nasal superior sector. Approximately half of the eyes with SSOH were classified as abnormal using indices developed for detecting glaucoma, but the sectorial analysis revealed that the affected sectors were different from those of glaucoma. Optic nerve head measurements using the HRT may be useful in evaluating the optic disc characteristics in eyes with SSOH.Keywords: superior segmental optic hypoplasia, Heidelberg retina tomography

  12. Macular Retinal Ganglion Cell Complex Thickness and Its Relationship to the Optic Nerve Head Topography in Glaucomatous Eyes with Hemifield Defects

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    Seiji T. Takagi

    2011-01-01

    Full Text Available Purpose. To evaluate the relationship between the macular ganglion cell complex (mGCC thickness, which is the sum of the retinal nerve fiber, ganglion cell, and inner plexiform layers, measured with a spectral-domain optical coherence tomograph and the optic nerve head topography measured with a confocal scanning laser ophthalmoscope in glaucomatous eyes with visual field defects localized predominantly to either hemifield. Materials and Methods. The correlation between the mGCC thickness in hemispheres corresponding to hemifields with and without defects (damaged and intact hemispheres, respectively and the optic nerve head topography corresponding to the respective hemispheres was evaluated in 18 glaucomatous eyes. Results. The mGCC thickness was significantly correlated with the rim volume, mean retinal nerve fiber layer thickness, and cross-sectional area of the retinal nerve fiber layer in both the intact and the damaged hemispheres (P<.05. Discussion. For detecting very early glaucomatous damage of the optic nerve, changes in the thicknesses of the inner retina in the macular area and peripapillary RNFL as well as rim volume changes in the optic nerve head are target parameters that should be carefully monitored.

  13. Breakdown of the normal optic nerve head blood-brain barrier following acute elevation of intraocular pressure in experimental animals.

    Science.gov (United States)

    Radius, R L; Anderson, D R

    1980-03-01

    Five hours of elevated intraocular pressure produced evidence of an altered blood-brain barrier at the optic nerve head in 27 of 29 monkey eyes. The change in vascular permeability was documented by fluorescein angiography (18 of 21 eyes), by Evans blue fluorescence microscopy (21 of 23 eyes), or by both methods. Leakage occurred from major blood vessels as well as from microvasculature of the nerve head. In 22 eyes, rapid axonal transport was studied after intravitreal injection of tritiated leucine. In 18 of these 22 eyes, autoradiography demonstrated a local interruption of axonal transport. In 15 eyes examined by all three methods, leakage from microvasculature (as opposed to leakage from the major vessels) was loosely associated with severe and widespread blockade of axonal transport at the lamina cribrosa. Although cause-and-effect relationships are not proved, ischemia may be responsible both for the focal endothelial damage with breakdown of the normal blood-brain barrier and for the local abnormalities of axonal transport.

  14. Oxidative injury to blood vessels and glia of the pre-laminar optic nerve head in human glaucoma.

    Science.gov (United States)

    Feilchenfeld, Zac; Yücel, Yeni H; Gupta, Neeru

    2008-11-01

    Glaucoma is a leading cause of irreversible world blindness. Oxidative damage and vascular injury have been implicated in the pathogenesis of this disease. The purpose of this study was to determine in human primary open angle glaucoma whether oxidative injury occurs in pre-laminar optic nerve blood vessels and glial cells. Following IRB approval, sections from post-mortem primary open angle glaucoma eyes (n=5) with mean age of 77 +/- 9 yrs (+/-SD) were compared to normal control eyes (n=4) with mean age 70 +/- 9 yrs (Eye Bank of Canada). Immunostaining with nitrotyrosine, a footprint for peroxynitrite-mediated injury, was performed and sections were double-labeled with markers for vascular endothelial cells, perivascular smooth muscle cells, and astrocytes with CD34, smooth muscle actin (SMA), and glial fibrillary acidic protein (GFAP), respectively. Immunostaining was captured in a masked fashion using confocal microscopy, and defined regions of interest for blood vessels and glial tissue. Intensity measurements of supra-threshold area in pixels as percent of the total number of pixels were calculated using ImageJ (NIH) and compared using two-tailed Mann-Whitney nonparametric tests between glaucoma and control groups. Colocalization coefficients with cell-specific markers were determined and compared with random coefficients of correlation. Increased nitrotyrosine immunoreactivity was observed in pre-laminar optic nerve head blood vessels of primary open angle glaucoma eyes compared to controls and this difference was statistically significant (1.35 +/- 1.11% [+/-SD] vs. 0.01 +/- 0.01%, P=0.016). NT-immunoreactivity was also increased in the glial tissue surrounding the pre-laminar optic nerve head in the glaucoma group and compared to controls, and this difference was statistically significant (18.37 +/-12.80% vs. 0.08 +/- 0.04%, P=0.016). Colocalization studies demonstrated nitrotyrosine staining in vascular endothelial and smooth muscle cells, in addition to

  15. Digital versus film stereo-photography for assessment of the optic nerve head in glaucoma and glaucoma suspect patients.

    Science.gov (United States)

    Hasanreisoglu, Murat; Priel, Ethan; Naveh, Lili; Lusky, Moshe; Weinberger, Dov; Benjamini, Yoav; Gaton, Dan D

    2013-03-01

    One of the leading methods for optic nerve head assessment in glaucoma remains stereoscopic photography. This study compared conventional film and digital stereoscopy in the quantitative and qualitative assessment of the optic nerve head in glaucoma and glaucoma suspect patients. Fifty patients with glaucoma or suspected glaucoma underwent stereoscopic photography of the optic nerve head with a 35-mm color slide film and a digital camera. Photographs/images were presented in random order to 3 glaucoma specialists for independent analysis using a standardized assessment form. Findings for the following parameters were compared among assessors and between techniques: cup/disc (C/D) ratio, state of the optic rim, presence of peripapillary atrophy and appearance of the retinal nerve fiber layer, blood vessels, and lamina cribrosa. The film-based and image-based diagnoses (glaucoma yes/no) were compared as well. Despite high level of agreement across graders using the same method for the horizontal and vertical C/D ratio, (intraclass correlations 0.80 to 0.83), the agreement across graders was much lower for the other parameters using the same method. Similarly the agreement between the findings of the same grader using either method was high for horizontal and vertical C/D ratio, but low for the other parameters. The latter differences were reflected in the disagreement regarding the final diagnosis: The diagnoses differed by technique for each grader in 18% to 46% of eyes, resulting in 38.5% of eyes diagnosed with glaucoma by film photography that "lost" their diagnosis on the digital images, whereas 18.7% of eyes diagnosed as nonglaucomatous by film photography were considered to have glaucoma on the digital images. Although there is consistency between 35-mm film stereoscopy and digital stereoscopy in determining the cup/disc (C/D) ratio, in all other parameters large differences exist, leading to differences in diagnosis. Differences in capturing images between

  16. Biomechanics of Cranio-Maxillofacial Trauma

    National Research Council Canada - National Science Library

    Pappachan, Biju; Alexander, Mohan

    .... This has got implications as facial fractures are associated with head injury. Understanding the biomechanics of craniomaxillofacial trauma gives an insight in understanding the pattern of injury...

  17. Design and validation of a method to determine the position of the fovea by using the nerve-head to fovea distance of the fellow eye.

    Directory of Open Access Journals (Sweden)

    Mathijs A J van de Put

    Full Text Available PURPOSE: To measure the nerve-head to fovea distance (NFD on fundus photographs in fellow eyes, and to compare the NFD between fellow eyes. METHODS: Diabetic patients without retinopathy, (n = 183 who were screened by fundus photography at the University Medical Center Groningen, the Netherlands from January 1(st 2005 until January 1(st 2006 were included. The NFD was measured in left and right eyes both from the center and from the rim of the nerve-head. To determine inter- and intra-observer agreement, repeated measurements by one observer (n = 3 were performed on all photographs and by two observers on 60 photographs (30 paired eyes. The effect of age, gender, and refractive error on NFD was analysed. RESULTS: The correlation of NFDs between the left and the right eye was 0.958 when measured from the center of the nerve head (mean difference 0.0078 mm. ±SD 0.079 (95% limits of agreement -0.147-0.163 and 0.963 when measured from the rim (mean difference 0.0056±SD 0.073 (95% limits of agreement -0.137-0.149. Using the NFD between fellow eyes interchangeably, resulted in a standard error of 0.153 mm. Intra- and inter-observer variability was small. We found a significant effect of age (center of the nerve-head (P = 0.006 and rim of the nerve head (P = 0.003 and refractive error (center of nerve-head (P<0.001 and rim of nerve head (P<0.001 on NFD. CONCLUSIONS: The NFD in one eye provides a confident, reproducible, and valid method to address the position of the fovea in the fellow eye. We recommend using the NFD measured from the center of the nerve-head since the standard error by this method was smallest. Age and refractive error have an effect on NFD.

  18. Effects of Head-down Tilt on Nerve Conduction in Rhesus Monkeys

    Directory of Open Access Journals (Sweden)

    Bo Sun

    2017-01-01

    Conclusions: This study demonstrates that the compound muscle action potential amplitudes of nerves are decreased under simulated microgravity in rhesus monkeys. Moreover, rhesus monkeys exposed to HDT might be served as an experimental model for the study of NCS under microgravity.

  19. Nerve sheath tumors of the head and neck - a radiological review; Tumores da bainha nervosa em cabeca e pescoco - estudo revisional

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Ricardo Pires de; Carramao, Cintia Fernandes; Soares, Aldemir Humberto [Hospital Heliopolis, Sao Paulo, SP (Brazil). Servico de Diagnostico por Imagem; Chacra Junior, Jose; Rapoport, Abrao [Hospital Heliopolis, Sao Paulo, SP (Brazil). Servico de Cirurgia de Cabeca e Pescoco

    1997-01-01

    Peripheral nerve sheath tumors of the head and neck - a review. Peripheral nerve sheath tumors are derived from neural crest and rare classified as neuroectodermal in origin. They can be divided into neurofibroma, schwannoma and neurogenic sarcoma. Neurofifromas are benign well circumscribed, nonencapsulated tumors which involve all elements of normal peripheral nerves. Schwannomas are beginning encapsulated tumors composed fundamentally by Schwann cells. Neurogenic sarcomas are malignant tumors which can be de novo or arise from preexisting neurofibroma or schwannoma. Peripheral nerve sheath tumors can arise from any nerve that contain myelin sheath, but are more frequent in extremities and trunk, being rare on cervical region. neurogenic tumors of head and neck can arise from cranial nerves, especially vagus nerve, brachial plexus and other small nervous plexus. Computed tomography and magnetic resonance imaging are the methods of choice in the evaluation of those tumors and can demonstrate lesions with several patterns. Areas of cystic degeneration are frequent in schwannomas, while neurofibromas are usually homogeneous. About 1/3 of those tumors are hyper vascularized and those who arise nervous spinal; roots can have an aspect of dumbbell which contain cervical and intravertebral components. (author) 51 refs., 5 figs.

  20. Optic Nerve Head and Retinal Nerve Fiber Layer Analysis in Ocular Hypertension and Early-Stage Glucoma Using Spectral-Domain Optical Coherence Tomography Copernicus

    Directory of Open Access Journals (Sweden)

    Nilgün Solmaz

    2014-01-01

    Full Text Available Objectives: Evaluation of structural alterations of the optic nerve head (ONH and the retinal nerve fiber layer (RNFL in patients with ocular hypertension (OHT and early-stage glaucoma and assessment of the discriminatory diagnostic performance of spectral-domain optical coherence tomography (SD-OCT Copernicus (Optopol Technology S.A.. Materials and Methods: This study included 59 eyes of a total of 59 patients, 29 of whom were diagnosed with OHT (Group 1 and 30 with early-stage glaucoma (Group 2. The differentiation of early-stage glaucoma and OHT was carried out on the basis of standard achromatic visual field test results. Analysis of the ONH and RNFL thickness of all cases was made using SD-OCT. Group 1 and Group 2 were compared with respect to the ONH parameters and RNFL thickness. The diagnostic sensitivity of the OCT parameters was evaluated by the area under the receiver operating characteristics curves (AUC. Results: The average, superior, inferior, and nasal RNFL thicknesses in early-stage glaucoma cases were approximately 10% (12-14 µm less compared to the OHT eyes, with differences being highly significant (p≤0.001. However, there was no statistically significant difference in the temporal RNFL thicknesses. The most sensitive parameter in the early diagnosis of glaucoma was average RNFL thickness corresponding to AUC: 0.852, followed by AUC: 0.816 and AUC: 0.773 values in superior and inferior RNFL thickness, respectively. In localized RNFL defects, the highest sensitivity corresponded to superior and superonasal quadrants (ACU: 0.805 and ACU: 0.781, respectively. There were not any statistically significant differences between the ONH morphological parameters of the two groups. Conclusion: RNFL analysis obtained using SD-OCT Copernicus is able to discriminate early-stage glaucoma eyes from those with OHT. However, ONH morphological parameters do not have the same diagnostic sensitivity. Turk J Ophthalmol 2014; 44: 35-41

  1. Spectral domain optical coherence tomography in glaucoma: qualitative and quantitative analysis of the optic nerve head and retinal nerve fiber layer (an AOS thesis).

    Science.gov (United States)

    Chen, Teresa C

    2009-12-01

    To demonstrate that video-rate spectral domain optical coherence tomography (SDOCT) can qualitatively and quantitatively evaluate optic nerve head (ONH) and retinal nerve fiber layer (RNFL) glaucomatous structural changes. To correlate quantitative SDOCT parameters with disc photography and visual fields. SDOCT images from 4 glaucoma eyes (4 patients) with varying stages of open-angle glaucoma (ie, early, moderate, late) were qualitatively contrasted with 2 age-matched normal eyes (2 patients). Of 61 other consecutive patients recruited in an institutional setting, 53 eyes (33 patients) met inclusion/exclusion criteria for quantitative studies. Images were obtained using two experimental SDOCT systems, one utilizing a superluminescent diode and the other a titanium:sapphire laser source, with axial resolutions of about 6 microm and 3 microm, respectively. Classic glaucomatous ONH and RNFL structural changes were seen in SDOCT images. An SDOCT reference plane 139 microm above the retinal pigment epithelium yielded cup-disc ratios that best correlated with masked physician disc photography cup-disc ratio assessments. The minimum distance band, a novel SDOCT neuroretinal rim parameter, showed good correlation with physician cup-disc ratio assessments, visual field mean deviation, and pattern standard deviation (P values range, .0003-.024). RNFL and retinal thickness maps correlated well with disc photography and visual field testing. To our knowledge, this thesis presents the first comprehensive qualitative and quantitative evaluation of SDOCT images of the ONH and RNFL in glaucoma. This pilot study provides basis for developing more automated quantitative SDOCT-specific glaucoma algorithms needed for future prospective multicenter national trials.

  2. Spectral Domain Optical Coherence Tomography in Glaucoma: Qualitative and Quantitative Analysis of the Optic Nerve Head and Retinal Nerve Fiber Layer (An AOS Thesis)

    Science.gov (United States)

    Chen, Teresa C.

    2009-01-01

    Purpose: To demonstrate that video-rate spectral domain optical coherence tomography (SDOCT) can qualitatively and quantitatively evaluate optic nerve head (ONH) and retinal nerve fiber layer (RNFL) glaucomatous structural changes. To correlate quantitative SDOCT parameters with disc photography and visual fields. Methods: SDOCT images from 4 glaucoma eyes (4 patients) with varying stages of open-angle glaucoma (ie, early, moderate, late) were qualitatively contrasted with 2 age-matched normal eyes (2 patients). Of 61 other consecutive patients recruited in an institutional setting, 53 eyes (33 patients) met inclusion/exclusion criteria for quantitative studies. Images were obtained using two experimental SDOCT systems, one utilizing a superluminescent diode and the other a titanium:sapphire laser source, with axial resolutions of about 6 μm and 3 μm, respectively. Results: Classic glaucomatous ONH and RNFL structural changes were seen in SDOCT images. An SDOCT reference plane 139 μm above the retinal pigment epithelium yielded cup-disc ratios that best correlated with masked physician disc photography cup-disc ratio assessments. The minimum distance band, a novel SDOCT neuroretinal rim parameter, showed good correlation with physician cup-disc ratio assessments, visual field mean deviation, and pattern standard deviation (P values range, .0003–.024). RNFL and retinal thickness maps correlated well with disc photography and visual field testing. Conclusions: To our knowledge, this thesis presents the first comprehensive qualitative and quantitative evaluation of SDOCT images of the ONH and RNFL in glaucoma. This pilot study provides basis for developing more automated quantitative SDOCT-specific glaucoma algorithms needed for future prospective multicenter national trials. PMID:20126502

  3. Numerical Optimization of the Position in Femoral Head of Proximal Locking Screws of Proximal Femoral Nail System; Biomechanical Study.

    Science.gov (United States)

    Konya, Mehmet Nuri; Verim, Özgür

    2017-09-29

    Proximal femoral fracture rates are increasing due to osteoporosis and traffic accidents. Proximal femoral nails are routinely used in the treatment of these fractures in the proximal femur. To compare various combinations and to determine the ideal proximal lag screw position in pertrochanteric fractures (Arbeitsgemeinschaft für Osteosynthesefragen classification 31-A1) of the femur by using optimized finite element analysis. Biomechanical study. Computed tomography images of patients' right femurs were processed with Mimics. Afterwards a solid femur model was created with SolidWorks 2015 and transferred to ANSYS Workbench 16.0 for response surface optimization analysis which was carried out according to anterior-posterior (-10°0) and posterior-anterior directions of the femur neck significantly increased these stresses. The most suitable position of the proximal lag screw was confirmed as the middle of the femoral neck by using optimized finite element analysis.

  4. Visualization of the 3-D topography of the optic nerve head through a passive stereo vision model

    Science.gov (United States)

    Ramirez, Juan M.; Mitra, Sunanda; Morales, Jose

    1999-01-01

    This paper describes a system for surface recovery and visualization of the 3D topography of the optic nerve head, as support of early diagnosis and follow up to glaucoma. In stereo vision, depth information is obtained from triangulation of corresponding points in a pair of stereo images. In this paper, the use of the cepstrum transformation as a disparity measurement technique between corresponding windows of different block sizes is described. This measurement process is embedded within a coarse-to-fine depth-from-stereo algorithm, providing an initial range map with the depth information encoded as gray levels. These sparse depth data are processed through a cubic B-spline interpolation technique in order to obtain a smoother representation. This methodology is being especially refined to be used with medical images for clinical evaluation of some eye diseases such as open angle glaucoma, and is currently under testing for clinical evaluation and analysis of reproducibility and accuracy.

  5. A joint estimation detection of Glaucoma progression in 3D spectral domain optical coherence tomography optic nerve head images.

    Science.gov (United States)

    Belghith, Akram; Bowd, Christopher; Weinreb, Robert N; Zangwill, Linda M

    2014-03-18

    Glaucoma is an ocular disease characterized by distinctive changes in the optic nerve head (ONH) and visual field. Glaucoma can strike without symptoms and causes blindness if it remains without treatment. Therefore, early disease detection is important so that treatment can be initiated and blindness prevented. In this context, important advances in technology for non-invasive imaging of the eye have been made providing quantitative tools to measure structural changes in ONH topography, an essential element for glaucoma detection and monitoring. 3D spectral domain optical coherence tomography (SD-OCT), an optical imaging technique, has been commonly used to discriminate glaucomatous from healthy subjects. In this paper, we present a new framework for detection of glaucoma progression using 3D SD-OCT images. In contrast to previous works that the retinal nerve fiber layer (RNFL) thickness measurement provided by commercially available spectral-domain optical coherence tomograph, we consider the whole 3D volume for change detection. To integrate a priori knowledge and in particular the spatial voxel dependency in the change detection map, we propose the use of the Markov Random Field to handle a such dependency. To accommodate the presence of false positive detection, the estimated change detection map is then used to classify a 3D SDOCT image into the "non-progressing" and "progressing" glaucoma classes, based on a fuzzy logic classifier. We compared the diagnostic performance of the proposed framework to existing methods of progression detection.

  6. Comparison of the Deep Optic Nerve Head Structure between Normal-Tension Glaucoma and Nonarteritic Anterior Ischemic Optic Neuropathy.

    Directory of Open Access Journals (Sweden)

    Eun Ji Lee

    Full Text Available To compare the deep optic nerve head (ONH structure between normal-tension glaucoma (NTG and nonarteritic anterior ischemic optic neuropathy (NAION and also in healthy subjects as a control using enhanced depth imaging (EDI spectral-domain optical coherence tomography (SD-OCT.This prospective cross-sectional study included 21 NAION patients who had been diagnosed as NAION at least 6 months prior to study entry, and 42 NTG patients and 42 healthy controls who were matched with NAION patients in terms of age, intraocular pressure (IOP, and optic disc area. The retinal nerve fiber layer (RNFL thickness in the affected sector was also matched between NAION and NTG patients. The ONH was imaged using SD-OCT with the EDI technique. The anterior lamina cribrosa surface depth (LCD and average prelaminar tissue (PT thickness were measured in a sector of interest in each eye and compared among the three groups.In the sector-matched comparison, LCD was largest in NTG patients, followed by NAION patients, while PT was thinner in NTG patients than in NAION patients (all P < 0.001. NAION patients had a comparable LCD and a thinner PT relative to normal controls (P = 0.170 and < 0.001, respectively.The deep ONH configuration is strikingly different between NTG and NAION. The differing features provide comparative insight into the pathophysiology of the two diseases, and may be useful for differential diagnosis.

  7. A joint estimation detection of Glaucoma progression in 3D spectral domain optical coherence tomography optic nerve head images

    Science.gov (United States)

    Belghith, Akram; Bowd, Christopher; Weinreb, Robert N.; Zangwill, Linda M.

    2014-03-01

    Glaucoma is an ocular disease characterized by distinctive changes in the optic nerve head (ONH) and visual field. Glaucoma can strike without symptoms and causes blindness if it remains without treatment. Therefore, early disease detection is important so that treatment can be initiated and blindness prevented. In this context, important advances in technology for non-invasive imaging of the eye have been made providing quantitative tools to measure structural changes in ONH topography, an essential element for glaucoma detection and monitoring. 3D spectral domain optical coherence tomography (SD-OCT), an optical imaging technique, has been commonly used to discriminate glaucomatous from healthy subjects. In this paper, we present a new framework for detection of glaucoma progression using 3D SD-OCT images. In contrast to previous works that the retinal nerve fiber layer (RNFL) thickness measurement provided by commercially available spectral-domain optical coherence tomograph, we consider the whole 3D volume for change detection. To integrate a priori knowledge and in particular the spatial voxel dependency in the change detection map, we propose the use of the Markov Random Field to handle a such dependency. To accommodate the presence of false positive detection, the estimated change detection map is then used to classify a 3D SDOCT image into the "non-progressing" and "progressing" glaucoma classes, based on a fuzzy logic classifier. We compared the diagnostic performance of the proposed framework to existing methods of progression detection.

  8. Miniplate With a Bendable C-Tube Head Allows the Clinician to Alter Biomechanical Advantage in Extremely Complicated Anatomic Structure.

    Science.gov (United States)

    Seo, Kyung Won; Iskenderoglu, Nur Serife; Hwang, Eui Hwan; Chung, Kyu-Rhim; Kim, Seong-Hun

    2017-05-01

    This article reports C-tube miniplates as a practical temporary anchorage device choice to treat open bite patients with maxillary sinus pneumatization. The C-tube components are titanium anchor plates and monocortical screws that are basically similar to any other miniplate systems, but it has the unique characteristic of the tube head to be malleable. The manipulation of the head part is easy due to the composition of pure titanium. The I-shaped C-tube with 3 holes and T-shaped C-tube miniplates were placed above the apices of maxillary molars as an absolute anchorage system to intrude the posterior maxilla. The bending of the tube heads assisted in reduction of severe open bite patient with maxillary sinus pneumatization. Sinus perforation during placement of skeletal anchorage system weakens stability of the anchorage and further cause complications. Placement of titanium C-tube miniplates allowed reliable skeletal anchorage and avoided maxillary sinus perforation in patients with extreme pneumatizations. Simple bending of C-tube miniplates ensured increased orthodontic intrusion force without having to replace them, and eliminated consequences such as perforation of maxillary sinus, sinusitis, soft tissue irritation, or infection. Anatomic difficulties in the placement of temporary anchorage device can be easily managed by using the bendable C-tube miniplate. It can serve as a great alternative over miniscrews or regular miniplates with reduced risk of sinus perforation and ability to bend the head portion to control orthodontic vectors and forces.

  9. Investigation of multiple optical and biometric properties of optic nerve head (Conference Presentation)

    Science.gov (United States)

    Hong, Young-Joo; Chan, Aaron C.; Kasaragod, Deepa K.; Makita, Shuichi; Miura, Masahiro; Yasuno, Yoshiaki

    2017-02-01

    Glaucoma is a group of eye diseases which results in optic nerve damage and vision loss. Optical coherence tomography (OCT) has been widely used to investigate geometric risk factor of glaucoma. However, material properties of ONH are also important to understand intra-ocular pressure related stress. We developed Jones-matrix based multifunctional posterior eye OCT (JM-OCT), which uses 1-μm band swept-source with a 100-kHz A-line rate. It provides three different optical properties, attenuation coefficient (AC), local birefringence (LB), and optical coherence angiography (OCA). We investigated the utility those properties for the investigation of normal ONH cases. 3 mm x 3 mm area around ONH was scanned for each eye, and biometric parameters were measured in hospital. Statistical analyses were performed with the mean values of above parameters at the regions of prelamina, lamina cribrosa, peripapillary sclera, and peripapillary nerve fiber layer, and biometric parameters of age, axial eye length, refractive error, and intraocular pressure. In qualitative observation, the lamina cribrosa generally shows more hyper signals in AC, LB, and OCA than prelamina. In t-test, AC, LB, and OCA showed significant difference (p eye length is positively correlated with LB and AC in lamina cribrosa. And these LB and AC are also negatively correlated with the refractive error. Age was found to be negatively correlated with OCA in lamina cribrosa.

  10. Sox10 Expression in Goldfish Retina and Optic Nerve Head in Controls and after the Application of Two Different Lesion Paradigms

    Science.gov (United States)

    Parrilla, Marta; León-Lobera, Fernando; Lillo, Concepción; Arévalo, Rosario; Aijón, José; Lara, Juan Manuel; Velasco, Almudena

    2016-01-01

    The mammalian central nervous system (CNS) is unable to regenerate. In contrast, the CNS of fish, including the visual system, is able to regenerate after damage. Moreover, the fish visual system grows continuously throughout the life of the animal, and it is therefore an excellent model to analyze processes of myelination and re-myelination after an injury. Here we analyze Sox10+ oligodendrocytes in the goldfish retina and optic nerve in controls and after two kinds of injuries: cryolesion of the peripheral growing zone and crushing of the optic nerve. We also analyze changes in a major component of myelin, myelin basic protein (MBP), as a marker for myelinated axons. Our results show that Sox10+ oligodendrocytes are located in the retinal nerve fiber layer and along the whole length of the optic nerve. MBP was found to occupy a similar location, although its loose appearance in the retina differed from the highly organized MBP+ axon bundles in the optic nerve. After optic nerve crushing, the number of Sox10+ cells decreased in the crushed area and in the optic nerve head. Consistent with this, myelination was highly reduced in both areas. In contrast, after cryolesion we did not find changes in the Sox10+ population, although we did detect some MBP- degenerating areas. We show that these modifications in Sox10+ oligodendrocytes are consistent with their role in oligodendrocyte identity, maintenance and survival, and we propose the optic nerve head as an excellent area for research aimed at better understanding of de- and remyelination processes. PMID:27149509

  11. Sox10 Expression in Goldfish Retina and Optic Nerve Head in Controls and after the Application of Two Different Lesion Paradigms.

    Directory of Open Access Journals (Sweden)

    Marta Parrilla

    Full Text Available The mammalian central nervous system (CNS is unable to regenerate. In contrast, the CNS of fish, including the visual system, is able to regenerate after damage. Moreover, the fish visual system grows continuously throughout the life of the animal, and it is therefore an excellent model to analyze processes of myelination and re-myelination after an injury. Here we analyze Sox10+ oligodendrocytes in the goldfish retina and optic nerve in controls and after two kinds of injuries: cryolesion of the peripheral growing zone and crushing of the optic nerve. We also analyze changes in a major component of myelin, myelin basic protein (MBP, as a marker for myelinated axons. Our results show that Sox10+ oligodendrocytes are located in the retinal nerve fiber layer and along the whole length of the optic nerve. MBP was found to occupy a similar location, although its loose appearance in the retina differed from the highly organized MBP+ axon bundles in the optic nerve. After optic nerve crushing, the number of Sox10+ cells decreased in the crushed area and in the optic nerve head. Consistent with this, myelination was highly reduced in both areas. In contrast, after cryolesion we did not find changes in the Sox10+ population, although we did detect some MBP- degenerating areas. We show that these modifications in Sox10+ oligodendrocytes are consistent with their role in oligodendrocyte identity, maintenance and survival, and we propose the optic nerve head as an excellent area for research aimed at better understanding of de- and remyelination processes.

  12. Three-dimensional interactive and stereotactic atlas of head muscles and glands correlated with cranial nerves and surface and sectional neuroanatomy.

    Science.gov (United States)

    Nowinski, Wieslaw L; Chua, Beng Choon; Johnson, Aleksandra; Qian, Guoyu; Poh, Lan Eng; Yi, Su Hnin Wut; Bivi, Aminah; Nowinska, Natalia G

    2013-04-30

    Three-dimensional (3D) relationships between head muscles and cranial nerves innervating them are complicated. Existing sources present these relationships in illustrations, radiologic scans, or autopsy photographs, which are limited for learning and use. Developed electronic atlases are limited in content, quality, functionality, and/or presentation. We create a truly 3D interactive, stereotactic and high quality atlas, which provides spatial relationships among head muscles, glands and cranial nerves, and correlates them to surface and sectional neuroanatomy. The head muscles and glands were created from a 3T scan by contouring them and generating 3D models. They were named and structured according to Terminologia anatomica. The muscles were divided into: extra-ocular, facial, masticatory and other muscles, and glands into mouth and other glands. The muscles, glands (and also head) were placed in a stereotactic coordinate system. This content was integrated with cranial nerves and neuroanatomy created earlier. To explore this complex content, a scalable user interface was designed with 12 modules including central nervous system (cerebrum, cerebellum, brainstem, spinal cord), cranial nerves, muscles, glands, arterial system, venous system, tracts, deep gray nuclei, ventricles, white matter, visual system, head. Anatomy exploration operations include compositing/decompositing, individual/group selection, 3D view-index mapping, 3D labeling, highlighting, distance measuring, 3D brain cutting, and axial/coronal/sagittal triplanar display. To our best knowledge, this is the first truly 3D, stereotactic, interactive, fairly complete atlas of head muscles, and the first attempt to create a 3D stereotactic atlas of glands. Its use ranges from education of students and patients to research to potential clinical applications.

  13. Acellular allogeneic nerve grafting combined with bone marrow mesenchymal stem cell transplantation for the repair of long-segment sciatic nerve defects:biomechanics and validation of mathematical models

    Institute of Scientific and Technical Information of China (English)

    Ya-jun Li; Bao-lin Zhao; Hao-ze Lv; Zhi-gang Qin; Min Luo

    2016-01-01

    We hypothesized that a chemically extracted acellular allogeneic nerve graft used in combination with bone marrow mesenchymal stem cell transplantation would be an effective treatment for long-segment sciatic nerve defects. To test this, we established rabbit models of 30 mm sciatic nerve defects, and treated them using either an autograft or a chemically decellularized allogeneic nerve graft with or without simultaneous transplantation of bone marrow mesenchymal stem cells. We compared the tensile properties, electrophysiological function and morphology of the damaged nerve in each group. Sciatic nerves repaired by the allogeneic nerve graft combined with stem cell trans-plantation showed better recovery than those repaired by the acellular allogeneic nerve graft alone, and produced similar results to those observed with the autograft. These ifndings conifrm that a chemically extracted acellular allogeneic nerve graft combined with transplanta-tion of bone marrow mesenchymal stem cells is an effective method of repairing long-segment sciatic nerve defects.

  14. Intraoperative radiation of canine carotid artery, internal jugular vein, and vagus nerve. Therapeutic applications in the management of advanced head and neck cancers

    Energy Technology Data Exchange (ETDEWEB)

    Mittal, B.B.; Pelzer, H.; Tsao, C.S.; Ward, W.F.; Johnson, P.; Friedman, C.; Sisson, G.A. Sr.; Kies, M. (Northwestern Univ., Chicago, IL (USA))

    1990-12-01

    As a step in the application of intraoperative radiotherapy (IORT) for treating advanced head and neck cancers, preliminary information was obtained on the radiation tolerance of the canine common carotid artery, internal jugular vein, and vagus nerve to a single, high-dose electron beam. Both sides of the neck of eight mongrel dogs were operated on to expose an 8-cm segment of common carotid artery, internal jugular vein, and vagus nerve. One side of the neck was irradiated, using escalating doses of 2500, 3500, 4500, and 5500 cGy. The contralateral side of the neck served as the unirradiated control. At 3 and 6 months after IORT, one dog at each dose level was killed. None of the dogs developed carotid bleeding at any time after IORT. Light microscopic investigations using hematoxylin-eosin staining on the common carotid artery and internal jugular vein showed no consistent changes that suggested radiation damage; however, the Masson trichrome stain and hydroxyproline concentration of irradiated common carotid artery indicated an increase in the collagen content of the tunica media. Marked changes in the irradiated vagus nerve were seen, indicating severe demyelination and loss of nerve fibers, which appeared to be radiation-dose dependent. Four patients with advanced recurrent head and neck cancer were treated with surgical resection and IORT without any acute or subacute complications. The role of IORT as a supplement to surgery, external beam irradiation, and chemotherapy in selected patients with advanced head and neck cancer needs further exploration.

  15. Scanning laser polarimetry reveals status of RNFL integrity in eyes with optic nerve head swelling by OCT.

    Science.gov (United States)

    Kupersmith, Mark J; Kardon, Randy; Durbin, Mary; Horne, Melissa; Shulman, Julia

    2012-04-18

    Optical coherence tomography (OCT) shows retinal nerve fiber layer (RNFL) thickening in optic nerve head (ONH) swelling, but does not provide information on acute axonal disruption. It was hypothesized that scanning laser polarimetry (SLP) compared with OCT might reveal the status of axon integrity and visual prognosis in acute RNFL swelling. Threshold perimetry, OCT, and SLP were used to prospectively study eyes with papilledema (24), optic neuritis (14), nonarteritic anterior ischemic optic neuropathy (NAION) (21), and ONH swelling (average RNFL value by OCT was above the 95th percentile of controls at presentation). Regional RNFL was judged reduced if the quadrant measurement was below the fifth percentile of controls. At presentation, average RNFL by OCT was similar for eyes with papilledema and NAION (P = 0.97), and reduced for optic neuritis. Average RNFL by SLP was slightly increased for papilledema and optic neuritis, and reduced for NAION (P = 0.02) eyes. The RNFL by SLP was reduced in at least one quadrant in 1 eye with papilledema, 1 eye with optic neuritis, and in 13 eyes with NAION. In NAION eyes, quadrants with reduced SLP had corresponding visual field loss that did not recover. By one month, eyes with NAION showed RNFL thinning by OCT (7/17 eyes) and by SLP (14/16 eyes) in contrast to optic neuritis (by OCT, 0/12, P = 0.006; and by SLP, 1/12, P = 0.0004). OCT and SLP revealed different aspects of RNFL changes associated with ONH swelling. OCT revealed thickening due to edema. SLP revealed a decrease in retardance in eyes with axonal injury associated with visual field loss, which is unlikely to recover.

  16. Confocal scanning laser tomography of the optic nerve head on the patients with Alzheimer's disease compared to glaucoma and control.

    Science.gov (United States)

    Kurna, Sevda Aydin; Akar, Gokcen; Altun, Ahmet; Agirman, Yasemin; Gozke, Eren; Sengor, Tomris

    2014-12-01

    The purpose of this study was to evaluate optic nerve head (ONH) differences of the patients with Alzheimer's disease (AD) measured by confocal scanning laser tomography [Heidelberg Retina Tomograph (HRT) III] and compare with glaucoma and control subjects. Eighty-four patients were enrolled into the study: 44 eyes of 24 patients with mild to moderate AD (Group 1), 68 eyes of 35 patients with glaucoma (Group 2), and 49 eyes of 25 heathy volunteers as a control (Group 3). A complete ophthalmologic examination as well as a confocal scanning laser ophthalmoscopic assessment with HRT III were performed on all patients. Mean values of the ONH topographic parameters such as rim area (RA), rim volume (RV), height variation contour, linear cup/disc ratio, cup shape measure, and retinal nerve fiber layer (RNFL) were recorded. Mean values of RNFL thickness was 0.23 ± 0.07 in AD, 0.22 ± 0.09 in glaucoma and 0.24 ± 0.07 in the control group (p = 0.323). RA and RV were significantly lower, and linear C/D ratio was significantly higher in the glaucoma group when compared to AD and control (p 0.05). We observed a negative correlation of the age with RNFL in all of the groups (p < 0.005). Age was the most important parameter affecting RNFL. Our results suggest that HRT does not demonstrate ONH differences between AD and control group, while it successfully differentiates glaucoma from AD and control cases of older age.

  17. CT, MRI, and (18)F-FDG PET/CT findings of malignant peripheral nerve sheath tumor of the head and neck.

    Science.gov (United States)

    Kim, Ha Youn; Hwang, Ji Young; Kim, Hyung-Jin; Kim, Yi Kyung; Cha, Jihoon; Park, Gyeong Min; Kim, Sung Tae

    2017-10-01

    Background Malignant peripheral nerve sheath tumor (MPNST) is a highly malignant tumor and rarely occurs in the head and neck. Purpose To describe the imaging features of MPNST of the head and neck. Material and Methods We retrospectively analyzed computed tomography (CT; n = 14), magnetic resonance imaging (MRI; n = 16), and (18)F-FDG PET/CT (n = 5) imaging features of 18 MPNSTs of the head and neck in 17 patients. Special attention was paid to determine the nerve of origin from which the tumor might have arisen. Results All lesions were well-defined (n = 3) or ill-defined (n = 15) masses (mean, 6.1 cm). Lesions were at various locations but most commonly the neck (n = 8), followed by the intracranial cavity (n = 3), paranasal sinus (n = 2), and orbit (n = 2). The nerve of origin was inferred for 11 lesions: seven in the neck, two in the orbit, one in the cerebellopontine angle, and one on the parietal scalp. Attenuation, signal intensity, and enhancement pattern of the lesions on CT and MRI were non-specific. Necrosis/hemorrhage/cystic change within the lesion was considered to be present on images in 13 and bone change in nine. On (18)F-FDG PET/CT images, all five lesions demonstrated various hypermetabolic foci with maximum standard uptake value (SUVmax) from 3.2 to 14.6 (mean, 7.16 ± 4.57). Conclusion MPNSTs can arise from various locations in the head and neck. Though non-specific, a mass with an ill-defined margin along the presumed course of the cranial nerves may aid the diagnosis of MPSNT in the head and neck.

  18. Translating ocular biomechanics into clinical practice: current state and future prospects.

    Science.gov (United States)

    Girard, Michaël J A; Dupps, William J; Baskaran, Mani; Scarcelli, Giuliano; Yun, Seok H; Quigley, Harry A; Sigal, Ian A; Strouthidis, Nicholas G

    2015-01-01

    Biomechanics is the study of the relationship between forces and function in living organisms and is thought to play a critical role in a significant number of ophthalmic disorders. This is not surprising, as the eye is a pressure vessel that requires a delicate balance of forces to maintain its homeostasis. Over the past few decades, basic science research in ophthalmology mostly confirmed that ocular biomechanics could explain in part the mechanisms involved in almost all major ophthalmic disorders such as optic nerve head neuropathies, angle closure, ametropia, presbyopia, cataract, corneal pathologies, retinal detachment and macular degeneration. Translational biomechanics in ophthalmology, however, is still in its infancy. It is believed that its use could make significant advances in diagnosis and treatment. Several translational biomechanics strategies are already emerging, such as corneal stiffening for the treatment of keratoconus, and more are likely to follow. This review aims to cultivate the idea that biomechanics plays a major role in ophthalmology and that the clinical translation, lead by collaborative teams of clinicians and biomedical engineers, will benefit our patients. Specifically, recent advances and future prospects in corneal, iris, trabecular meshwork, crystalline lens, scleral and lamina cribrosa biomechanics are discussed.

  19. Optic nerve head slope-based quantitative parameters for identifying open-angle glaucoma on SPECTRALIS OCT images.

    Science.gov (United States)

    Al-Hinnawi, Abdel-Razzak M; Al-Naami, Bassam O; Al-Latayfeh, Motasem M

    2017-08-01

    To investigate monitoring slope-based features of the optic nerve head (ONH) cup as open-angle glaucoma (OAG) occurs. A dataset of 46 retrospective OCT cases was acquired from the SPECTRALIS Heidelberg Engineering OCT device. A set of five parameters, which are based on the ONH cup-incline, are measured on the OAG and normal subjects in the dataset. Then, three new ONH cup-shape indices were deduced. The ONH cup-incline parameters and ONH cup-shape indices are analyzed to estimate their clinical value. The statistical difference between measurements on normal and glaucoma eyes was remarkably significant for all of the analyzed parameters and indices (p value < 0.001). The geometric shape of the ONH cup can be transferred to numerical parameters and indices. The proposed ONH cup-incline parameters and ONH cup-shape indices have shown suggestive clinical value to identify the development of OAG. As OAG appears, the top ONH cup-incline parameters decrease while the bottom ONH cup-incline parameters increase. The ONH cup-shape indices suggest capability to discriminate OAG from normal eyes.

  20. Graph search: active appearance model based automated segmentation of retinal layers for optic nerve head centered OCT images

    Science.gov (United States)

    Gao, Enting; Shi, Fei; Zhu, Weifang; Jin, Chao; Sun, Min; Chen, Haoyu; Chen, Xinjian

    2017-02-01

    In this paper, a novel approach combining the active appearance model (AAM) and graph search is proposed to segment retinal layers for optic nerve head(ONH) centered optical coherence tomography(OCT) images. The method includes two parts: preprocessing and layer segmentation. During the preprocessing phase, images is first filtered for denoising, then the B-scans are flattened. During layer segmentation, the AAM is first used to obtain the coarse segmentation results. Then a multi-resolution GS-AAM algorithm is applied to further refine the results, in which AAM is efficiently integrated into the graph search segmentation process. The proposed method was tested on a dataset which contained113-D SD-OCT images, and compared to the manual tracings of two observers on all the volumetric scans. The overall mean border positioning error for layer segmentation was found to be 7.09 +/- 6.18μm for normal subjects. It was comparable to the results of traditional graph search method (8.03+/-10.47μm) and mean inter-observer variability (6.35+/-6.93μm).The preliminary results demonstrated the feasibility and efficiency of the proposed method.

  1. Automated discovery of structural features of the optic nerve head on the basis of image and genetic data

    Science.gov (United States)

    Christopher, Mark; Tang, Li; Fingert, John H.; Scheetz, Todd E.; Abramoff, Michael D.

    2014-03-01

    Evaluation of optic nerve head (ONH) structure is a commonly used clinical technique for both diagnosis and monitoring of glaucoma. Glaucoma is associated with characteristic changes in the structure of the ONH. We present a method for computationally identifying ONH structural features using both imaging and genetic data from a large cohort of participants at risk for primary open angle glaucoma (POAG). Using 1054 participants from the Ocular Hypertension Treatment Study, ONH structure was measured by application of a stereo correspondence algorithm to stereo fundus images. In addition, the genotypes of several known POAG genetic risk factors were considered for each participant. ONH structural features were discovered using both a principal component analysis approach to identify the major modes of variance within structural measurements and a linear discriminant analysis approach to capture the relationship between genetic risk factors and ONH structure. The identified ONH structural features were evaluated based on the strength of their associations with genotype and development of POAG by the end of the OHTS study. ONH structural features with strong associations with genotype were identified for each of the genetic loci considered. Several identified ONH structural features were significantly associated (p genetic risk status was found to substantially increase performance of early POAG prediction. These results suggest incorporating both imaging and genetic data into ONH structural modeling significantly improves the ability to explain POAG-related changes to ONH structure.

  2. 3-D segmentation of retinal blood vessels in spectral-domain OCT volumes of the optic nerve head

    Science.gov (United States)

    Lee, Kyungmoo; Abràmoff, Michael D.; Niemeijer, Meindert; Garvin, Mona K.; Sonka, Milan

    2010-03-01

    Segmentation of retinal blood vessels can provide important information for detecting and tracking retinal vascular diseases including diabetic retinopathy, arterial hypertension, arteriosclerosis and retinopathy of prematurity (ROP). Many studies on 2-D segmentation of retinal blood vessels from a variety of medical images have been performed. However, 3-D segmentation of retinal blood vessels from spectral-domain optical coherence tomography (OCT) volumes, which is capable of providing geometrically accurate vessel models, to the best of our knowledge, has not been previously studied. The purpose of this study is to develop and evaluate a method that can automatically detect 3-D retinal blood vessels from spectral-domain OCT scans centered on the optic nerve head (ONH). The proposed method utilized a fast multiscale 3-D graph search to segment retinal surfaces as well as a triangular mesh-based 3-D graph search to detect retinal blood vessels. An experiment on 30 ONH-centered OCT scans (15 right eye scans and 15 left eye scans) from 15 subjects was performed, and the mean unsigned error in 3-D of the computer segmentations compared with the independent standard obtained from a retinal specialist was 3.4 +/- 2.5 voxels (0.10 +/- 0.07 mm).

  3. Electrical Stimulation of the Ear, Head, Cranial Nerve, or Cortex for the Treatment of Tinnitus: A Scoping Review

    Directory of Open Access Journals (Sweden)

    Derek J. Hoare

    2016-01-01

    Full Text Available Tinnitus is defined as the perception of sound in the absence of an external source. It is often associated with hearing loss and is thought to result from abnormal neural activity at some point or points in the auditory pathway, which is incorrectly interpreted by the brain as an actual sound. Neurostimulation therapies therefore, which interfere on some level with that abnormal activity, are a logical approach to treatment. For tinnitus, where the pathological neuronal activity might be associated with auditory and other areas of the brain, interventions using electromagnetic, electrical, or acoustic stimuli separately, or paired electrical and acoustic stimuli, have been proposed as treatments. Neurostimulation therapies should modulate neural activity to deliver a permanent reduction in tinnitus percept by driving the neuroplastic changes necessary to interrupt abnormal levels of oscillatory cortical activity and restore typical levels of activity. This change in activity should alter or interrupt the tinnitus percept (reduction or extinction making it less bothersome. Here we review developments in therapies involving electrical stimulation of the ear, head, cranial nerve, or cortex in the treatment of tinnitus which demonstrably, or are hypothesised to, interrupt pathological neuronal activity in the cortex associated with tinnitus.

  4. Advances in biomechanical studies on osteonecrosis of the femoral head%股骨头缺血性坏死相关生物力学研究进展

    Institute of Scientific and Technical Information of China (English)

    陈雷雷; 何伟

    2011-01-01

    Osteonecrosis of the femoral head is a common clinical orthopedic disease. The progression of the disease is rapid and the prognosis is poor. All the medical profession recognize it as one of the unresolved medical problems. Biomechanical factors play an important role in the course of progression and treatment of osteonecrosis of the femoral head. In this paper,we review the literature and introduce the advanced biomechanical studies on the symptoms ,image,collapse ,collapse prediction, preserving femoral head surgery of osteonecrosis of the femoral head.%股骨头缺血性坏死是一种临床常见的骨科疾病,病情发展迅速,预后较差,是医学界公认的治疗难题.在股骨头缺血性坏死病程发展及治疗中,生物力学因素起着重要的作用.本文对股骨头缺血性坏死症状、影像学、塌陷、预测塌陷、保髋治疗等方面的相关生物力学国内外研究现状做一综述.

  5. Autofluorescence spectroscopy for nerve-sparing laser surgery of the head and neck-the influence of laser-tissue interaction.

    Science.gov (United States)

    Stelzle, Florian; Rohde, Maximilian; Riemann, Max; Oetter, Nicolai; Adler, Werner; Tangermann-Gerk, Katja; Schmidt, Michael; Knipfer, Christian

    2017-08-01

    The use of remote optical feedback systems represents a promising approach for minimally invasive, nerve-sparing laser surgery. Autofluorescence properties can be exploited for a fast, robust identification of nervous tissue. With regard to the crucial step towards clinical application, the impact of laser ablation on optical properties in the vicinity of structures of the head and neck has not been investigated up to now. We acquired 24,298 autofluorescence spectra from 135 tissue samples (nine ex vivo tissue types from 15 bisected pig heads) both before and after ER:YAG laser ablation. Sensitivities, specificities, and area under curve(AUC) values for each tissue pair as well as the confusion matrix were statistically calculated for pre-ablation and post-ablation autofluorescence spectra using principal component analysis (PCA), quadratic discriminant analysis (QDA), and receiver operating characteristics (ROC). The confusion matrix indicated a highly successful tissue discrimination rate before laser exposure, with an average classification error of 5.2%. The clinically relevant tissue pairs nerve/cancellous bone and nerve/salivary gland yielded an AUC of 100% each. After laser ablation, tissue discrimination was feasible with an average classification accuracy of 92.1% (average classification error 7.9%). The identification of nerve versus cancellous bone and salivary gland performed very well with an AUC of 100 and 99%, respectively. Nerve-sparing laser surgery in the area of the head and neck by means of an autofluorescence-based feedback system is feasible even after ER-YAG laser-tissue interactions. These results represent a crucial step for the development of a clinically applicable feedback tool for laser surgery interventions in the oral and maxillofacial region.

  6. Retinal and choroidal oxygen saturation of the optic nerve head in open-angle glaucoma subjects by multispectral imaging.

    Science.gov (United States)

    Li, Gai-Yun; Al-Wesabi, Samer Abdo; Zhang, Hong

    2016-12-01

    The aim of this study was to determine whether differences exist in oxygen supply to the optic nerve head (ONH) from the retinal and choroidal vascular layers in patients with primary open angle glaucoma (POAG) using multispectral imaging (MSI).This ia an observational, cross-sectional study.Multispectral images were acquired from 38 eyes of 19 patients with POAG, and 42 healthy eyes from 21 matched volunteers with Annidis' RHA multispectral digital ophthalmoscopy. Superficial and deeper oxygen saturation of the optic disc was represented by the mean gray scale values on the retinal and choroidal oxy-deoxy maps, respectively. Statistical analysis was performed to detect differences in ONH oxygen saturation between the 2 groups. Oxygen saturation levels in the eyes of POAG patients with severe glaucoma were compared to those of fellow eyes from the same subjects. Linear correlation analysis was performed to assess the association between ONH oxygen saturation and systemic and ocular parameters.No statistical difference was found in retinal and choroidal oxygen saturation between the POAG and control groups. In the glaucoma patients, retinal oxygen saturation was lower for eyes with worse visual fields than in those with good visual fields (t = 4.009, P = 0.001). In POAG patients, retinal oxygen saturation was dependent on mean defect of visual field and retinal nerve fiber layer thickness (RNFLT) (r = 0.511, 0.504, P = 0.001, 0.001, respectively), whereas the choroid vasculature oxygen saturation was inversely related to RNFLT (r = -0.391, P = 0.015). An age-dependent increase in retinal oxygen saturation was found for both the POAG and control groups (r = 0.473, 0.410, P = 0.007, 0.003, respectively).MSI revealed a significant correlation between functional and structural impairments in glaucoma and retinal oxygen saturation. MSI could provide objective assessments of perfusion impairments of the glaucomatous ONH. This is a

  7. Spectral domain optical coherence tomography cross-sectional image of optic nerve head during intraocular pressure elevation

    Directory of Open Access Journals (Sweden)

    Ji Young Lee

    2014-12-01

    Full Text Available AIM: To analyze changes of the optic nerve head (ONH and peripapillary region during intraocular pressure (IOP elevation in patients using spectral domain optical coherence tomography (SD-OCT.METHODS: Both an optic disc 200×200 cube scan and a high-definition 5-line raster scan were obtained from open angle glaucoma patients presented with monocular elevation of IOP (≥30 mm Hg using SD-OCT. Additional baseline characteristics included age, gender, diagnosis, best-corrected visual acuity, refractive error, findings of slit lamp biomicroscopy, findings of dilated stereoscopic examination of the ONH and fundus, IOP, pachymetry findings, and the results of visual field.RESULTS: The 24 patients were selected and divided into two groups:group 1 patients had no history of IOP elevation or glaucoma (n=14, and group 2 patients did have history of IOP elevation or glaucoma (n=10. In each patient, the study eye with elevated IOP was classified into group H (high, and the fellow eye was classified into group L (low. The mean deviation (MD differed significantly between groups H and L when all eyes were considered (P=0.047 and in group 2 (P=0.042, not in group 1 (P=0.893. Retinal nerve fiber layer (RNFL average thickness (P=0.050, rim area (P=0.015, vertical cup/disc ratio (P=0.011, cup volume (P=0.028, inferior quadrant RNFL thickness (P=0.017, and clock-hour (1, 5, and 6 RNFL thicknesses (P=0.050, 0.012, and 0.018, respectively, cup depth (P=0.008, central prelaminar layer thickness (P=0.023, mid-inferior prelaminar layer thickness (P=0.023, and nasal retinal slope (P=0.034 were significantly different between the eyes with groups H and L.CONCLUSION:RNFL average thickness, rim area, vertical cup/disc ratio, cup volume, inferior quadrant RNFL thickness, and clock-hour (1, 5, and 6 RNFL thicknesses significantly changed during acute IOP elevation.

  8. Ability of Optic Nerve Head Examination, Heidelberg Retina Tomograph’s Moorfield’s Regression Analysis, and Glaucoma Probability Score

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    F. Saenz-Frances

    2015-01-01

    Full Text Available Purpose. To study whether a corneal thickness segmentation model, consisting in a central circular zone of 1 mm radius centered at the corneal apex (zone I and five concentric rings of 1 mm width (moving outwards: zones II to VI, could boost the diagnostic accuracy of Heidelberg Retina Tomograph’s (HRT’s MRA and GPS. Material and Methods. Cross-sectional study. 121 healthy volunteers and 125 patients with primary open-angle glaucoma. Six binary multivariate logistic regression models were constructed (MOD-A1, MOD-A2, MOD-B1, MOD-B2, MOD-C1, and MOD-C2. The dependent variable was the presence of glaucoma. In MOD-A1, the predictor was the result (presence of glaucoma of the analysis of the stereophotography of the optic nerve head (ONH. In MOD-B1 and MOD-C1, the predictor was the result of the MRA and GPS, respectively. In MOD-B2 and MOD-C2, the predictors were the same along with corneal variables: central, overall, and zones I to VI thicknesses. This scheme was reproduced for model MOD-A2 (stereophotography along with corneal variables. Models were compared using the area under the receiver operator characteristic curve (AUC. Results. MOD-A1-AUC: 0.771; MOD-A2-AUC: 0.88; MOD-B1-AUC: 0.736; MOD-B2-AUC: 0.845; MOD-C1-AUC: 0.712; MOD-C2-AUC: 0.838. Conclusion. Corneal thickness variables enhance ONH assessment and HRT’s MRA and GPS diagnostic capacity.

  9. Osteopontin is induced by TGF-β2 and regulates metabolic cell activity in cultured human optic nerve head astrocytes.

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    Carolin Neumann

    Full Text Available The aqueous humor (AH component transforming growth factor (TGF-β2 is strongly correlated to primary open-angle glaucoma (POAG, and was shown to up-regulate glaucoma-associated extracellular matrix (ECM components, members of the ECM degradation system and heat shock proteins (HSP in primary ocular cells. Here we present osteopontin (OPN as a new TGF-β2 responsive factor in cultured human optic nerve head (ONH astrocytes. Activation was initially demonstrated by Oligo GEArray microarray and confirmed by semiquantitative (sq RT-PCR, realtime RT-PCR and western blot. Expressions of most prevalent OPN receptors CD44 and integrin receptor subunits αV, α4, α 5, α6, α9, β1, β3 and β5 by ONH astrocytes were shown by sqRT-PCR and immunofluorescence labeling. TGF-β2 treatment did not affect their expression levels. OPN did not regulate gene expression of described TGF-β2 targets shown by sqRT-PCR. In MTS-assays, OPN had a time- and dose-dependent stimulating effect on the metabolic activity of ONH astrocytes, whereas TGF-β2 significantly reduced metabolism. OPN signaling via CD44 mediated a repressive outcome on metabolic activity, whereas signaling via integrin receptors resulted in a pro-metabolic effect. In summary, our findings characterize OPN as a TGF-β2 responsive factor that is not involved in TGF-β2 mediated ECM and HSP modulation, but affects the metabolic activity of astrocytes. A potential involvement in a protective response to TGF-β2 triggered damage is indicated, but requires further investigation.

  10. Neovibsanin B increases extracellular matrix proteins in optic nerve head cells via activation of Smad signalling pathway.

    Science.gov (United States)

    Wang, Zhen; Xu, Wei; Rong, Ao; Lin, Yan; Qiu, Xu-Ling; Qu, Shen; Lan, Xian-Hai

    2015-01-01

    The present study demonstrates the effect of neovibsanin B on the synthesis and deposition of ECM proteins and the signalling pathways used in optic nerve head (ONH) astrocytes and lamina cribrosa (LC) cells. For investigation of the signalling pathway used by neovibsanin B, ONH cells were treated with neovibsanin B. Western blot and immunostaining analyses were used to examine the phosphorylation of proteins involved in Smad and non-Smad signalling pathway. The results revealed that ONH cells on treatment with neovibsanin B showed enhanced synthesis of extracellular matrix (ECM) proteins. Neovibsanin B induced phosphorylation of canonical signalling proteins, Smad2/3. However phosphorylation of non-canonical signalling proteins, extracellular signal-regulated kinases, p38, and c-Jun N-terminal kinases (JNK) 1/2 remained unaffected. There was also increase in co-localization of pSmad2/3 with Co-Smad4 in the nucleus of ONH astrocytes and LC cells indicating activation of the canonical Smad signalling pathway. Treatment of ONH cells with SIS3, inhibitor of Smad3 phosphorylation reversed the neovibsanin B stimulated ECM expression as well as activation of canonical pathway signalling molecules. In addition, inhibition of Smad2 or Smad3 using small interfering RNA (siRNA) also suppressed neovibsanin B stimulated ECM protein synthesis in ONH astrocytes and LC cells. Thus neovibsanin B utilizes the canonical Smad signalling pathway to stimulate ECM synthesis in human ONH cells. The neovibsanin B induced ECM synthesis and activation of the canonical Smad signalling pathway may be due to its effect on transforming growth factor-β2 (TGF-β2). However, further studies are under process to understand the mechanism.

  11. Variation in response dynamics of regular and irregular vestibular-nerve afferents during sinusoidal head rotations and currents in the chinchilla.

    Science.gov (United States)

    Kim, Kyu-Sung; Minor, Lloyd B; Della Santina, Charles C; Lasker, David M

    2011-05-01

    In mammals, vestibular-nerve afferents that innervate only type I hair cells (calyx-only afferents) respond nearly in phase with head acceleration for high-frequency motion, whereas afferents that innervate both type I and type II (dimorphic) or only type II (bouton-only) hair cells respond more in phase with head velocity. Afferents that exhibit irregular background discharge rates have a larger phase lead re-head velocity than those that fire more regularly. The goal of this study was to investigate the cause of the variation in phase lead between regular and irregular afferents at high-frequency head rotations. Under the assumption that externally applied galvanic currents act directly on the nerve, we derived a transfer function describing the dynamics of a semicircular canal and its hair cells through comparison of responses to sinusoidally modulated head velocity and currents. Responses of all afferents were fit well with a transfer function with one zero (lead term). Best-fit lead terms describing responses to current for each group of afferents were similar to the lead term describing responses to head velocity for regular afferents (0.006 s + 1). This finding indicated that the pre-synaptic and synaptic inputs to regular afferents were likely to be pure velocity transducers. However, the variation in phase lead between regular and irregular afferents could not be explained solely by the ratio of type I to II hair cells (Baird et al 1988), suggesting that the variation was caused by a combination of pre- (type of hair cell) and post-synaptic properties.

  12. The relationship between lingual and hypoglossal nerve function and quality of life in head and neck cancer.

    Science.gov (United States)

    Elfring, T; Boliek, C A; Winget, M; Paulsen, C; Seikaly, H; Rieger, J M

    2014-02-01

    Sensorimotor impairment of the tongue has the potential to affect speech and swallowing. The purpose of this study was to critically examine the effects of nerve preservation and reinnervation after reconstruction of the base of tongue on patient-perceived outcomes of quality of life (QoL) related to speech and swallowing through completion of the EORTC QLQ-H&N35 standardised questionnaire. Thirty participants with a diagnosis of base of tongue cancer underwent primary resection and reconstruction with a radial forearm free flap, which may or may not have included nerve repair to the lingual nerve, hypoglossal nerve or both. Eight QoL domains sensitive to changes in motor and sensory nerve function were included in the analysis. Transected lingual and hypoglossal nerves were associated with difficulty in swallowing, social eating, dry mouth and social contact. There were fewer problems reported when these nerves were either repaired or left intact. There were no significant differences between patient nerve status and QoL outcomes for speech, sticky saliva and use of feeding tubes. This study was the first to examine the impact of sensory or motor nerve transection and reconstruction on health-related QoL outcomes. © 2013 John Wiley & Sons Ltd.

  13. Effect of pillow height on the biomechanics of the head-neck complex: investigation of the cranio-cervical pressure and cervical spine alignment

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    Sicong Ren

    2016-08-01

    spine alignment were height-specific, and they were believed to reflect quality of sleep. Our results provide a quantitative and objective evaluation of the effect of pillow height on the biomechanics of the head-neck complex, and have application in pillow design and selection.

  14. Effect of pillow height on the biomechanics of the head-neck complex: investigation of the cranio-cervical pressure and cervical spine alignment.

    Science.gov (United States)

    Ren, Sicong; Wong, Duo Wai-Chi; Yang, Hui; Zhou, Yan; Lin, Jin; Zhang, Ming

    2016-01-01

    quantitative and objective evaluation of the effect of pillow height on the biomechanics of the head-neck complex, and have application in pillow design and selection.

  15. Head MRI

    Science.gov (United States)

    ... heart valves Heart defibrillator or pacemaker Inner ear (cochlear) implants Kidney disease or dialysis (you may not ... to: Abnormal blood vessels in the brain ( arteriovenous malformations of the head ) Tumor of the nerve that ...

  16. Comparison of optic area measurement using fundus photography and optical coherence tomography between optic nerve head drusen and control subjects.

    Science.gov (United States)

    Flores-Rodríguez, Patricia; Gili, Pablo; Martín-Ríos, María Dolores; Grifol-Clar, Eulalia

    2013-03-01

    To compare optic disc area measurement between optic nerve head drusen (ONHD) and control subjects using fundus photography, time-domain optical coherence tomography (TD-OCT) and spectral-domain optical coherence tomography (SD-OCT). We also made a comparison between each of the three techniques. We performed our study on 66 eyes (66 patients) with ONHD and 70 healthy control subjects (70 controls) with colour ocular fundus photography at 20º (Zeiss FF 450 IR plus), TD-OCT (Stratus OCT) with the Fast Optic Disc protocol and SD-OCT (Cirrus OCT) with the Optic Disc Cube 200 × 200 protocol for measurement of the optic disc area. The measurements were made by two observers and in each measurement a correction of the image magnification factor was performed. Measurement comparison using the Student's t-test/Mann-Whitney U test, the intraclass correlation coefficient, Pearson/Spearman rank correlation coefficient and the Bland-Altman plot was performed in the statistical analysis. Mean and standard deviation (SD) of the optic disc area in ONHD and in controls was 2.38 (0.54) mm(2) and 2.54 (0.42) mm(2), respectively with fundus photography; 2.01 (0.56) mm(2) and 1.66 (0.37) mm(2), respectively with TD-OCT, and 2.03 (0.49) mm(2) and 1.75 (0.38) mm(2), respectively with SD-OCT. In ONHD and controls, repeatability of optic disc area measurement was excellent with fundus photography and optical coherence tomography (TD-OCT and SD-OCT), but with a low degree of agreement between both techniques. Optic disc area measurement is smaller in ONHD compared to healthy subjects with fundus photography, unlike time-domain and spectral-domain optical coherence tomography in which the reverse is true. Both techniques offer good repeatability, but a low degree of correlation and agreement, which means that optic disc area measurement is not interchangeable or comparable between techniques. Ophthalmic & Physiological Optics © 2013 The College of Optometrists.

  17. Biomechanics of foetal movement

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    N.C. Nowlan

    2015-01-01

    Full Text Available Foetal movements commence at seven weeks of gestation, with the foetal movement repertoire including twitches, whole body movements, stretches, isolated limb movements, breathing movements, head and neck movements, jaw movements (including yawning, sucking and swallowing and hiccups by ten weeks of gestational age. There are two key biomechanical aspects to gross foetal movements; the first being that the foetus moves in a dynamically changing constrained physical environment in which the freedom to move becomes increasingly restricted with increasing foetal size and decreasing amniotic fluid. Therefore, the mechanical environment experienced by the foetus affects its ability to move freely. Secondly, the mechanical forces induced by foetal movements are crucial for normal skeletal development, as evidenced by a number of conditions and syndromes for which reduced or abnormal foetal movements are implicated, such as developmental dysplasia of the hip, arthrogryposis and foetal akinesia deformation sequence. This review examines both the biomechanical effects of the physical environment on foetal movements through discussion of intrauterine factors, such as space, foetal positioning and volume of amniotic fluid, and the biomechanical role of gross foetal movements in human skeletal development through investigation of the effects of abnormal movement on the bones and joints. This review also highlights computational simulations of foetal movements that attempt to determine the mechanical forces acting on the foetus as it moves. Finally, avenues for future research into foetal movement biomechanics are highlighted, which have potential impact for a diverse range of fields including foetal medicine, musculoskeletal disorders and tissue engineering.

  18. Biomechanics of foetal movement.

    Science.gov (United States)

    Nowlan, N C

    2015-01-02

    Foetal movements commence at seven weeks of gestation, with the foetal movement repertoire including twitches, whole body movements, stretches, isolated limb movements, breathing movements, head and neck movements, jaw movements (including yawning, sucking and swallowing) and hiccups by ten weeks of gestational age. There are two key biomechanical aspects to gross foetal movements; the first being that the foetus moves in a dynamically changing constrained physical environment in which the freedom to move becomes increasingly restricted with increasing foetal size and decreasing amniotic fluid. Therefore, the mechanical environment experienced by the foetus affects its ability to move freely. Secondly, the mechanical forces induced by foetal movements are crucial for normal skeletal development, as evidenced by a number of conditions and syndromes for which reduced or abnormal foetal movements are implicated, such as developmental dysplasia of the hip, arthrogryposis and foetal akinesia deformation sequence. This review examines both the biomechanical effects of the physical environment on foetal movements through discussion of intrauterine factors, such as space, foetal positioning and volume of amniotic fluid, and the biomechanical role of gross foetal movements in human skeletal development through investigation of the effects of abnormal movement on the bones and joints. This review also highlights computational simulations of foetal movements that attempt to determine the mechanical forces acting on the foetus as it moves. Finally, avenues for future research into foetal movement biomechanics are highlighted, which have potential impact for a diverse range of fields including foetal medicine, musculoskeletal disorders and tissue engineering.

  19. Impact of intraocular pressure on changes of blood flow in the retina, choroid, and optic nerve head in rats investigated by optical microangiography

    OpenAIRE

    Zhi, Zhongwei; Cepurna, William O.; Johnson, Elaine C.; Morrison, John C.; Wang, Ruikang K.

    2012-01-01

    In this paper, we demonstrate the use of optical coherence tomography/optical microangiography (OCT/OMAG) to image and measure the effects of acute intraocular pressure (IOP) elevation on retinal, choroidal and optic nerve head (ONH) perfusion in the rat eye. In the experiments, IOP was elevated from 10 to 100 mmHg in 10 mmHg increments. At each IOP level, three-dimensional data volumes were captured using an ultrahigh sensitive (UHS) OMAG scanning protocol for 3D volumetric perfusion imaging...

  20. 视神经减压术对颅脑损伤合并视神经损伤视力康复的意义%The significance of decompression of optic nerve in the rehabilitation of traumatic optic nerve following head trauma

    Institute of Scientific and Technical Information of China (English)

    邱建武; 宋振全; 林军

    2002-01-01

    Objective To investigate the significance of decompression of optic nerve in the rehabilitation of traumatic optic neuropathy following head trauma.Method Surgical treatment was performed on 16 patients suffered from traumatic neuropathy following head trauma.Fragments ,hematoma,necrotic brain tissue resulting from fracture of orbital bone were removed and frontal and orbital fracture or malposition corrected by craniotomy through valve of frontal bone in 15 patients.Optic canal was probed and sheath of optic nerve was cut open for decompression of optic nerve.Frontotemporal wound was made in 1 case with superior orbital fissure syndrome and decompression of optic canal and abrasion of superior orbital fissure were performed through outer side of orbital point.Result Surgical treatment was effective in 12 cases(75% ),exophthalmus in 2 cases was corrected.Conclusion Decompression of optic nerve through frontal bone or frontotemporal is effective in enhancing visual acuity in patients with traumatic optic neuropathy following head trauma.

  1. Biomechanics Significance of Femoral Head and Neck of Grafting-bone Group After Femoral Neck Fracture-healing%股骨颈骨折愈合后钉道植骨的生物力学意义

    Institute of Scientific and Technical Information of China (English)

    唐洪涛; 仝允辉; 杨茹萍; 朱太永; 张美超; 赵卫东

    2011-01-01

    Objective To study biomechanical performance of fracture-healing femoral head and neck after the hollow compressionb screws are taken out in ungrafting-bone group, grafting-bone group, normal group, and provide theoretical basis for the treatment of necrosis of the femoral head by bone grafting in the channel of screws. Methods Nine femurs fixed and preserved by formalin were used in this test. They were randomly divided into three groups: normal group, ungrafting-bone group, grafting-bone group. According to inversed-triangle, at the range of physiological load, it tested the defixed bias-value of three group femoral head at different load. The data were collected and analyzed. The three-dimension finite element model of the femoral head and neck was calculated. Nodal solution of stress value and max-offset was calculated at area of femoral head and neck, then the data were compared and analyzed.Results Compared with the mean of load-offset about the femoral head and neck, biomechanical capability of ungrafting-bone group was lowest with regard to other two groups , the influence was very hard, P <0.05. But there was no singnificant difference between normal group and graflng-bone group, P >0.05. Analysis of the three-dimension finite element model showed that the massive stress was concentrated at weight loading region of ungrafting-bone group's femoral head, it was an dangerous chance to lead to femoral head collapse. Conclusion For the treatment of femur neck fractures with cannulated compression screws, bone grafting in the channel of screw should be used to improve biomechanical integrity after fracture healed and cannulated compression screws are taken out. This is of benefit to loading in early stage and to preventing the collapse of femoral head, etc.%目的 探讨股骨颈骨折愈合后取出空心加压螺钉遗留钉道不植骨、植骨及正常的股骨头颈部的生物力学特性,为临床提供实验依据.方法 收集9付股骨标本测量

  2. Acupuncture therapy to the head and face to treat post-trauma paralysis of peripheral fascial nerve dextra

    Science.gov (United States)

    Mihardja, H.; Meuratana, PA; Ibrahim, A.

    2017-08-01

    Damage to the facial nerve due to trauma from traffic accidents is the second most common cause of paralysis of the facial nerve. The treatments include both pharmacological and non-pharmacological therapy. Acupuncture is a method of treatment that applies evidence-based medical principles and uses anatomy, physiology, and pathology to place needles atcertain acupuncture points. This paper describes a 26-year-old female patient with right-side facial palsy following a traffic accident who had animproved Brackmann’s score after 12 sessions of acupuncture treatment. The acupuncture points were chosen based on Liu Yan’sbrain-clearing needling technique. Acupuncture can shorten healing time and improve the effect of treatment for facial-nerve paralysis.

  3. Expression of Glucose Transporters in the Prelaminar Region of the Optic-Nerve Head of the Pig as Determined by Immunolabeling and Tissue Culture

    Science.gov (United States)

    Carreras, F. Javier; Aranda, Carlos J.; Porcel, David; Rodriguez-Hurtado, Francisco; Martínez-Agustin, Olga; Zarzuelo, Antonio

    2015-01-01

    Background To develop the use of cultured tissue of the prelaminar optic nerve of the pig to explore possible alterations of the astrocyte-axon metabolic pathways in glaucoma, we map the distribution of the glucose transporters GLUT1 and GLUT3 in fresh and cultured tissue. Methods We monitor cell survival in cultures of the prelaminar optic-nerve tissue, measuring necrosis and apoptosis markers biochemically as well as morphologically, and establish the presence of the glucose transporters GLUT1 and GLUT3. We map the distribution of these transporters with immunolabeling in histological sections of the optic nerve using confocal and electronic transmission microscopy. Results We find that the main death type in prelaminar culture is apoptosis. Caspase 7 staining reveals an increment in apoptosis from day 1 to day 4 and a reduction from day 4 to day 8. Western blotting for GLUT1 shows stability with increased culture time. CLSM micrographs locate GLUT1 in the columnar astrocytes and in the area of axonal bundles. Anti-GLUT3 predominantly labels axonal bundles. TEM immunolabeling with colloidal gold displays a very specific distribution of GLUT-1 in the membranes of vascular endothelial cells and in periaxonal astrocyte expansions. The GLUT-3 isoform is observed with TEM only in axons in the axonal bundles. Conclusions Tissue culture is suitable for apoptosis-induction experiments. The results suggest that glucose is transported to the axonal cleft intracytoplasmically and delivered to the cleft by GLUT1 transporters. As monocarboxylate transporters have been reported in the prelaminar region of the optic-nerve head, this area is likely to use both lactate and glucose as energy sources. PMID:26030125

  4. Expression of glucose transporters in the prelaminar region of the optic-nerve head of the pig as determined by immunolabeling and tissue culture.

    Directory of Open Access Journals (Sweden)

    F Javier Carreras

    Full Text Available To develop the use of cultured tissue of the prelaminar optic nerve of the pig to explore possible alterations of the astrocyte-axon metabolic pathways in glaucoma, we map the distribution of the glucose transporters GLUT1 and GLUT3 in fresh and cultured tissue.We monitor cell survival in cultures of the prelaminar optic-nerve tissue, measuring necrosis and apoptosis markers biochemically as well as morphologically, and establish the presence of the glucose transporters GLUT1 and GLUT3. We map the distribution of these transporters with immunolabeling in histological sections of the optic nerve using confocal and electronic transmission microscopy.We find that the main death type in prelaminar culture is apoptosis. Caspase 7 staining reveals an increment in apoptosis from day 1 to day 4 and a reduction from day 4 to day 8. Western blotting for GLUT1 shows stability with increased culture time. CLSM micrographs locate GLUT1 in the columnar astrocytes and in the area of axonal bundles. Anti-GLUT3 predominantly labels axonal bundles. TEM immunolabeling with colloidal gold displays a very specific distribution of GLUT-1 in the membranes of vascular endothelial cells and in periaxonal astrocyte expansions. The GLUT-3 isoform is observed with TEM only in axons in the axonal bundles.Tissue culture is suitable for apoptosis-induction experiments. The results suggest that glucose is transported to the axonal cleft intracytoplasmically and delivered to the cleft by GLUT1 transporters. As monocarboxylate transporters have been reported in the prelaminar region of the optic-nerve head, this area is likely to use both lactate and glucose as energy sources.

  5. Study on the influence of the fetus head molding on the biomechanical behavior of the pelvic floor muscles, during vaginal delivery.

    Science.gov (United States)

    Silva, M E T; Oliveira, D A; Roza, T H; Brandão, S; Parente, M P L; Mascarenhas, T; Natal Jorge, R M

    2015-06-25

    Pelvic floor injuries during vaginal delivery are considered a significant risk factor to develop pelvic floor dysfunction. The molding of the fetus head during vaginal delivery facilitates the labor progress, since it adjusts to the birth canal geometry. In this work, a finite element model was used to represent the effects induced by the passage of the fetus head on the pelvic floor. The numerical model used for this simulation included the pelvic floor muscles attached to the bones, and a fetus body. The model of the fetus head included the skin and soft tissues, the skull with sutures and fontanelles, and the brain. The fetus head movements during birth in vertex position were simulated: descent, internal rotation and extension. Two models of the fetus head were compared: a rigid and a deformable one, with the inclusion of the cranial sutures. The influence of the fetus head molding on the pelvic floor muscles was analyzed by evaluating their reaction forces, stretch, and stress and strain fields. Additionally, anatomical indices for the molding of the fetal skull were obtained and compared with clinical data. The passage of the deformable fetus head through the birth canal leads to a reduction of 17.3% on the reaction forces on the pelvic floor muscles when compared to the ones of a rigid head. Furthermore, the fetus head molding implies inferior resistance to rotation resulting in a reduction of 1.86% in muscle stretching. Quantitative evaluation of the fetus head molding showed good agreement with clinical experiments.

  6. Size of the Optic Nerve Head and Its Relationship with the Thickness of the Macular Ganglion Cell Complex and Peripapillary Retinal Nerve Fiber Layer in Patients with Primary Open Angle Glaucoma

    Directory of Open Access Journals (Sweden)

    Nobuko Enomoto

    2015-01-01

    Full Text Available Purpose. To evaluate the relationships among the optic nerve head (ONH area, macular ganglion cell complex (mGCC thickness, circumpapillary retinal nerve fiber layer (cpRNFL thickness, and visual field defects in patients with primary open angle glaucoma (POAG. Methods. This retrospective study included 90 eyes of 90 patients with POAG. The ONH area, rim area, mGCC thickness, and cpRNFL thickness were measured using optical coherence tomography. Mean deviation (MD was measured using standard automated perimetry. The relationships among clinical factors including age, refraction, the ONH area, the rim area, the mGCC thickness, the cpRNFL thickness, and MD were evaluated using correlation coefficients and multiple regression analyses. Results. The significant correlation of the ONH area with refraction (r=0.362, P<0.001, the mGCC thickness (r=0.225, P=0.033, and the cpRNFL thickness (r=0.253, P=0.016 was found. Multiple regression analysis showed that the ONH area, rim area, and MD were selected as significant contributing factors to explain the mGCC thickness and cpRNFL thickness. No factor was selected to explain MD. Conclusions. The ONH area, in other words, the disc size itself may affect the mGCC thickness and cpRNFL thickness in POAG patients.

  7. Association between Optic Nerve Head Microcirculation and Macular Ganglion Cell Complex Thickness in Eyes with Untreated Normal Tension Glaucoma and a Hemifield Defect

    Directory of Open Access Journals (Sweden)

    Ayako Anraku

    2017-01-01

    Full Text Available Purpose. We evaluated the association between optic nerve head (ONH microcirculation and macular ganglion cell complex (mGCC thickness in patients with untreated normal tension glaucoma (NTG and a hemifield defect. Methods. The medical records of 47 patients with untreated NTG were retrospectively reviewed. Laser speckle flowgraphy was used to obtain mean blur rate (MBR, a relative measure of blood flow. Average total deviation (TD, mGCC, and the circumpapillary retinal nerve fiber layer (cpRNFL thickness were also analyzed. Results. All parameters corresponding to the defective hemifield were significantly lower than those corresponding to the normal hemifield. In the defective hemifield, MBR was correlated with TD, mGCC, and cpRNFL thickness. In the normal hemifield, MBR was only correlated with mGCC thickness, and multiple regression analysis showed that mGCC thickness was a significant contributing factor of the MBR. Conclusion. MBR was well correlated with mGCC thickness in eyes with untreated NTG and a hemifield defect. In the normal hemifield, mGCC thickness was a contributing factor of the MBR indicating that ONH circulatory dysfunction may be associated with retinal structural changes in the early stages of glaucoma. A reduction in ONH microcirculation may be an early indicator of the presence and progression of glaucoma.

  8. [Evaluation of the injured range of vestibular superior and inferior nerves in sudden deafness patients with vertigo using video head impulse test].

    Science.gov (United States)

    Hou, Lingxiao; Chen, Taisheng; Xu, Kaixu; Wang, Wei; Li, Shanshan; Liu, Qiang; Wen, Chao; Cheng, Yan; Zhao, Hui; Ma, Yuanxu; Lin, Peng

    2015-09-01

    To discuss the video head impulse tests (vHIT) application values in assessment of the vestibular nerves, function in sudden deafness patients with vertigo. There were 60 cases (120 ears) of healthy volunteers as control group, and 182 cases (182 ears) of sudden deafness with vertigo patients as study group. The study group received vHIT and caloric test, and the control group received vHIT. Functions of vestibular superior and inferior nerves were analyzed by the gains of vHIT and the nystagmus, s unilateral weakness of caloric test, with SPSS17.0 software. The values of vHIT-G of the six semicircular canals in the control group were normal distribution and no statistical significance among them (F = 0.005, P = 1.000). The vHIT-G averages of both sides of anterior, horizontal and posterior semicircular canals were (15.20 ± 11.00) %, (15.30 ± 13.30) %, and (15.15 ± 14.72) % respectively. In the study group, the vHIT-G of the affected side were (21.73 ± 14.84) %, (21.20 ± 28.24) %, and (19.22 ± 23.50) %, with normal distribution, and in which statistical significance was detected comparing with those in the control group (P sudden deafness patients with vertigo.

  9. Biomechanical patterns of text-message distraction.

    Science.gov (United States)

    Le, Peter; Hwang, Jaejin; Grawe, Sarah; Li, Jing; Snyder, Alison; Lee, Christina; Marras, William S

    2015-01-01

    The objective of this study was to identify biomechanical measures that can distinguish texting distraction in a laboratory-simulated driving environment. The goal would be to use this information to provide an intervention for risky driving behaviour. Sixteen subjects participated in this study. Three independent variables were tested: task (texting, visual targeting, weighted and non-weighted movements), task direction (front and side) and task distance (close and far). Dependent variables consisted of biomechanical moments, head displacement and the length of time to complete each task. Results revealed that the time to complete each task was higher for texting compared to other tasks. Peak moments during texting were only distinguishable from visual targeting. Peak head displacement and cumulative biomechanical exposure measures indicated that texting can be distinguished from other tasks. Therefore, it may be useful to take into account both temporal and biomechanical measures when considering warning systems to detect texting distraction.

  10. Ultrasonographic assessment of carpal tunnel biomechanics

    NARCIS (Netherlands)

    van Doesburg, M.H.M.

    2012-01-01

    In this thesis, we searched for a way to assess flexor tendon and median nerve biomechanics, as well as subsynovial connective tissue thickness (SSCT) in the carpal tunnel with ultrasound, and tried to see if these patterns would give a clue towards understanding the etiology of carpal tunnel syndro

  11. Nerve Transfers to Restore Shoulder Function.

    Science.gov (United States)

    Leechavengvongs, Somsak; Malungpaishorpe, Kanchai; Uerpairojkit, Chairoj; Ng, Chye Yew; Witoonchart, Kiat

    2016-05-01

    The restoration of shoulder function after brachial plexus injury represents a significant challenge facing the peripheral nerve surgeons. This is owing to a combination of the complex biomechanics of the shoulder girdle, the multitude of muscles and nerves that could be potentially injured, and a limited number of donor options. In general, nerve transfer is favored over tendon transfer, because the biomechanics of the musculotendinous units are not altered. This article summarizes the surgical techniques and clinical results of nerve transfers for restoration of shoulder function.

  12. Dinosaur biomechanics

    OpenAIRE

    Alexander, R. McNeill

    2006-01-01

    Biomechanics has made large contributions to dinosaur biology. It has enabled us to estimate both the speeds at which dinosaurs generally moved and the maximum speeds of which they may have been capable. It has told us about the range of postures they could have adopted, for locomotion and for feeding, and about the problems of blood circulation in sauropods with very long necks. It has made it possible to calculate the bite forces of predators such as Tyrannosaurus, and the stresses they imp...

  13. Shoulder biomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Lugo, Roberto; Kung, Peter; Ma, C. Benjamin [Sports Medicine and Shoulder Service, University of California, San Francisco, 500 Parnassus Avenue, MU 320W-0728 San Francisco, CA 914143 (United States)], E-mail: maben@orthosurg.ucsf.edu

    2008-10-15

    The biomechanics of the glenohumeral joint depend on the interaction of both static and dynamic-stabilizing structures. Static stabilizers include the bony anatomy, negative intra-articular pressure, the glenoid labrum, and the glenohumeral ligaments along with the joint capsule. The dynamic-stabilizing structures include the rotator cuff muscles and the other muscular structures surrounding the shoulder joint. The combined effect of these stabilizers is to support the multiple degrees of motion within the glenohumeral joint. The goal of this article is to review how these structures interact to provide optimal stability and how failure of some of these mechanisms can lead to shoulder joint pathology.

  14. Optic nerve oxygen tension

    DEFF Research Database (Denmark)

    la Cour, M; Kiilgaard, Jens Folke; Eysteinsson, T

    2000-01-01

    To investigate the influence of acute changes in intraocular pressure on the oxygen tension in the vicinity of the optic nerve head under control conditions and after intravenous administration of 500 mg of the carbonic anhydrase inhibitor dorzolamide....

  15. On seed physiology, biomechanics and plant phenology in Eragrostis tef

    NARCIS (Netherlands)

    Delden, van S.H.

    2011-01-01

    • Key words: Teff (Eragrostis tef (Zuccagni) Trotter), germination, temperature, model, leaf appearance, phyllochron, development rate, lodging, biomechanics, safety factor, flowering, heading, day length, photoperiod. • Background Teff (Eragrostis tef (Zuccagni) Trotter) is a C4 annual g

  16. Hyperemic responses of the optic nerve head blood flow to chromatic equiluminant flicker are reduced by ocular hypertension and early glaucoma

    Science.gov (United States)

    Falsini, Benedetto; Riva, Charles E.; Salgarello, Tommaso; Logean, Eric; Colotto, Alberto; Giudiceandrea, Andrea

    2014-06-01

    We evaluated in ocular hypertension (OHT) and early glaucoma (EOAG) patients the optic nerve head (ONH) blood flow response (RF) to chromatic equiluminant flicker. This stimulus generates neural activity dominated by the parvo-cellular system. Eleven EOAG, 20 OHT patients, and 8 age-matched control subjects were examined. The blood flow (F) at the neuroretinal rim was continuously monitored by laser Doppler flowmetry before, during, and after a 60-s exposure to a 4 Hz, red-green equiluminant flicker stimulus (30 deg field). RF was expressed as percentage F-change during the last 20 s of flicker relative to baseline F. Responses were collected at a number of temporal sites. The highest RF value was used for subsequent analysis. As compared to controls, both OHT and EOAG patients showed a decrease (pRF. We conclude that RF elicited by chromatic equiluminant flicker is abnormally reduced in OHT and EOAG patients indicating an impairment of the parvo-cellular-mediated vasoactivity. This decrease of vascular response may occur independently of neural activity loss early in the disease process.

  17. Pulse-Wave Analysis of Optic Nerve Head Circulation Is Significantly Correlated with Kidney Function in Patients with and without Chronic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Tomoaki Shiba

    2014-01-01

    Full Text Available Aim. To determine whether there is a significant correlation between the optic nerve head (ONH circulation determined by laser speckle flowgraphy (LSFG and kidney function. Materials. Seventy-one subjects were investigated. The estimated glomerular filtration rate (GFR and serum creatinine, cystatin C, and urinary albumin excretion were measured. The ONH circulation was determined by an analysis of the pulse wave of LSFG, and this parameter was named blowout time (BOT. Chronic kidney disease (CKD was defined to be present when the estimated GFR was <60 mL/min per 1.73 m2. Pearson’s correlation coefficients were used to determine the relationship between the BOT and the kidney function. We also examined whether there were significant differences in all parameters in patients with and without CKD. Results. BOT was significantly correlated with the level of creatinine (r=-0.24, P=0.04, the estimated GFR (r=0.42, P=0.0003, cystatin C (r=-0.29, P=0.01, and urinary albumin excretion (r=-0.29, P=0.01. The BOT level in subjects with CKD was significantly lower than that in subjects without CKD (P=0.002. Conclusion. BOT in ONH by LSFG can detect the organ damage such as kidney dysfunction, CKD.

  18. Sensitivity and specificity of monochromatic photography of the ocular fundus in differentiating optic nerve head drusen and optic disc oedema: optic disc drusen and oedema.

    Science.gov (United States)

    Gili, Pablo; Flores-Rodríguez, Patricia; Yangüela, Julio; Orduña-Azcona, Javier; Martín-Ríos, María Dolores

    2013-03-01

    Evaluation of the efficacy of monochromatic photography of the ocular fundus in differentiating optic nerve head drusen (ONHD) and optic disc oedema (ODE). Sixty-six patients with ONHD, 31 patients with ODE and 70 healthy subjects were studied. Colour and monochromatic fundus photography with different filters (green, red and autofluorescence) were performed. The results were analysed blindly by two observers. The sensitivity, specificity and interobserver agreement (k) of each test were assessed. Colour photography offers 65.5 % sensitivity and 100 % specificity for the diagnosis of ONHD. Monochromatic photography improves sensitivity and specificity and provides similar results: green filter (71.20 % sensitivity, 96.70 % specificity), red filter (80.30 % sensitivity, 96.80 % specificity), and autofluorescence technique (87.8 % sensitivity, 100 % specificity). The interobserver agreement was good with all techniques used: autofluorescence (k = 0.957), green filter (k = 0.897), red filter (k = 0.818) and colour (k = 0.809). Monochromatic fundus photography permits ONHD and ODE to be differentiated, with good sensitivity and very high specificity. The best results were obtained with autofluorescence and red filter study.

  19. Cost-effective instrumentation for quantitative depth measurement of optic nerve head using stereo fundus image pair and image cross correlation techniques

    Science.gov (United States)

    de Carvalho, Luis Alberto V.; Carvalho, Valeria

    2014-02-01

    One of the main problems with glaucoma throughout the world is that there are typically no symptoms in the early stages. Many people who have the disease do not know they have it and by the time one finds out, the disease is usually in an advanced stage. Most retinal cameras available in the market today use sophisticated optics and have several other features/capabilities (wide-angle optics, red-free and angiography filters, etc) that make them expensive for the general practice or for screening purposes. Therefore, it is important to develop instrumentation that is fast, effective and economic, in order to reach the mass public in the general eye-care centers. In this work, we have constructed the hardware and software of a cost-effective and non-mydriatic prototype device that allows fast capturing and plotting of high-resolution quantitative 3D images and videos of the optical disc head and neighboring region (30° of field of view). The main application of this device is for glaucoma screening, although it may also be useful for the diagnosis of other pathologies related to the optic nerve.

  20. Soft tissue landmark for ultrasound identification of the sciatic nerve in the infragluteal region: the tendon of the long head of the biceps femoris muscle.

    NARCIS (Netherlands)

    Bruhn, J.; Moayeri, N.; Groen, G.J.; Veenendaal, A. van; Gielen, M.J.M.; Scheffer, G.J.; Geffen, G.J. van

    2009-01-01

    BACKGROUND AND OBJECTIVES: The sciatic nerve block represents one of the more difficult ultrasound-guided nerve blocks. Easy and reliable internal ultrasound landmarks would be helpful for localization of the sciatic nerve. Earlier, during ultrasound-guided posterior approaches to the infragluteal s

  1. Morphometric Optic Nerve Head Analysis in Glaucoma Patients: A Comparison between the Simultaneous Nonmydriatic Stereoscopic Fundus Camera (Kowa Nonmyd WX3D and the Heidelberg Scanning Laser Ophthalmoscope (HRT III

    Directory of Open Access Journals (Sweden)

    Siegfried Mariacher

    2016-01-01

    Full Text Available Purpose. To investigate the agreement between morphometric optic nerve head parameters assessed with the confocal laser ophthalmoscope HRT III and the stereoscopic fundus camera Kowa nonmyd WX3D retrospectively. Methods. Morphometric optic nerve head parameters of 40 eyes of 40 patients with primary open angle glaucoma were analyzed regarding their vertical cup-to-disc-ratio (CDR. Vertical CDR, disc area, cup volume, rim volume, and maximum cup depth were assessed with both devices by one examiner. Mean bias and limits of agreement (95% CI were obtained using scatter plots and Bland-Altman analysis. Results. Overall vertical CDR comparison between HRT III and Kowa nonmyd WX3D measurements showed a mean difference (limits of agreement of −0.06 (−0.36 to 0.24. For the CDR < 0.5 group (n=24 mean difference in vertical CDR was −0.14 (−0.34 to 0.06 and for the CDR ≥ 0.5 group (n=16 0.06 (−0.21 to 0.34. Conclusion. This study showed a good agreement between Kowa nonmyd WX3D and HRT III with regard to widely used optic nerve head parameters in patients with glaucomatous optic neuropathy. However, data from Kowa nonmyd WX3D exhibited the tendency to measure larger CDR values than HRT III in the group with CDR < 0.5 group and lower CDR values in the group with CDR ≥ 0.5.

  2. Shape variation of optic nerve head by mechanical analysis using three-dimensional finite element model%三维有限元模型力学分析可预测视乳头的形状变化

    Institute of Scientific and Technical Information of China (English)

    祁昕征; 魏超; 杨佳燕; 穆晶; 张昆亚; 刘志成; 钱秀清

    2013-01-01

    BACKGROUND:The measure and prediction of the shape of optic nerve head are the key issues for early diagnosis and duration prediction of glaucoma. Therefore, it is significant to research the shape variation of optic nerve head under high intraocular pressure. OBJECTIVE:To establish three-dimensional finite element model of optic nerve head and to analyze the deformation of optic nerve head and the change in retina thickness after acute high intraocular pressure. METHODS:Animal model of acute ocular hypertension was established by methods of anterior chamber perfusion. The tomographic images of the optic nerve head of a cat were obtained at the normal intraocular pressure and 5 320 Pa, 7 980 Pa, 10 640 Pa, 13 300 Pa, 15 960 Pa intraocular pressures using optical coherence tomography. Then, we measured the variation of retinal thickness at typical location. Basing on the tomographic images of optic nerve head of a cat at normal intraocular pressure, we obtained three-dimensional structure of retina and choroid using software MIMICS. Then three-dimensional model of optic nerve head was established by assembling the retina and choroid. The deformation of optic nerve head and the change in retinal thickness under high intraocular pressure were observed using software ABAQUS. The effectiveness of the model was verified by the experimental result. RESULTS AND CONCLUSION:With the increase of intraocular pressure, the retinal thickness is thinner, the optic nerve head depth, width and the ratio of the depth to width are gradual y increased. It suggests that the acute high intraocular pressure causes retinal thinning, optic nerve head widening and deepening. It is feasible to establish optic nerve head modeling in vivo by using optical coherence tomography, mechanical analysis can be applied to predict the shape variation of optic nerve head, which is significant to further deduce the pathological process of glaucoma.%背景:视乳头形状变化的准确测量及预测

  3. Effects of different tunnel sizes of femoral head core decompression on femoral neck biomechanics%股骨头钻孔减压孔径对股骨颈生物力学影响的实验研究

    Institute of Scientific and Technical Information of China (English)

    何国忠; 庞清江; 陈先军; 余霄; 赵卫东

    2013-01-01

    Objective To observe the effects of different tunnel sizes of the femoral head core decompression on femoral neck biomechanics. Methods 24 fresh cadaver femur specimens were randomly divided into four groups: a normal group, a single-tunnel core decompression group (D=10 mm), a 2-tunnel core decompression group (D=7mm) and a 3- tunnel core decompression group (D=7mm). 3 points in main tension side, main pressure side and the lesser trochanter were chosen as the test points of strain from ON to 1200N load. Results The strain of the 2-tunnel group was the lowest among the normal group, the single-tunnel group, 2-tunnel group and 3-tunnel group; furthermore, the strain values of all of the 3 core decompression groups were larger than that in the normal group in tension side and the pressure side. Conclusions There is a significant effect on the femoral neck biomechanics by femoral head core decompression. The 2-tunnel (D= 7mm) with the lowest strain value may be the best choice to femoral head core decompression.%目的 观察经转子间股骨头减压钻孔的孔径对股骨颈生物力学的影响.方法 取新鲜尸体股骨标本24具,随机分成4组:正常组、单孔减压组(D=10 mm)、双孔减压组(D=7 mm)和3孔减压组(D=7 mm).在股骨颈主张力侧、主压力侧和小转子处各选择1点作为应变测试点,检测4组标本在,0~1200N分级载荷下各测点的应变.结果 在股骨颈主张力侧和主压力侧的测试点中,单孔减压组、双孔减压组和3孔减压组的应变值均大于正常组,其中双孔减压组的应变值在三组钻孔组间最小,并且与其它组间相比差异具有显著性(P<0.05).结论 经转子间股骨头钻孔减压明显影响股骨颈生物力学性能,与单纯大孔钻孔面积相同的2小孔钻孔减压对股骨颈生物力学性能影响较小.

  4. Neuroretinal rim in non-glaucomatous large optic nerve heads: a comparison of confocal scanning laser tomography and spectral domain optical coherence tomography.

    Science.gov (United States)

    Enders, Philip; Schaub, Friederike; Hermann, Manuel M; Cursiefen, Claus; Heindl, Ludwig M

    2017-02-01

    To compare margin-based rim area measurements from confocal scanning laser tomography (CSLT) with Bruch's membrane opening (BMO)-based measurements from spectral domain optical coherence tomography (SD-OCT) by analysis of a group of non-glaucomatous eyes with large optic discs, so-called macrodiscs (disc size >2.45 mm(2) in CSLT). Objective is to create a reference base for large optic nerve heads in SD-OCT diagnostics. 102 eyes received CSLT and SD-OCT measurements and clinical examination on the same day. Visual field testing confirmed absence of glaucomatous defects. Statistical and correlation analysis was performed for rim area by CSLT as well as retinal nerve fibre layer thickness (RNFLT) and BMO minimal rim width (BMO-MRW) by SD-OCT. Mean disc size in CSLT was 2.98±0.4 mm(2) (range 2.45-4.23), mean rim area of 1.55±0.4 mm(2). BMO area was 2.51±0.33 mm(2) (range 1.61-3.51), mean global RNFLT was 79.55±17.2 μm, mean global BMO-MRW was 234.84±48.3 μm. Correlation of BMO-MRW to global RNFLT was stronger (r=0.60, p<10(-5)) than correlation of CSLT rim area to global RNFLT (r=0.26, p=0.24). BMO-MRW and CSLT rim area correlated with r=0.59 (p<10(-5)). BMO-MRW and RNFLT significantly decreased with increasing age (p<0.001). Annual loss of BMO-MRW was 0.8 μm/year (R(2)=0.14, p<0.001), loss of RNFLT was 0.27 μm/year (R(2)=0.17, p=0.001). In large optic discs, BMO-MRW is thinner compared with normal-sized discs and correlates better than CSLT parameters with the RNFLT. An age-depended loss of BMO-MRW needs to be taken into account in evaluation of the neuroretinal rim. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  5. The use of Bruch's membrane opening-based optical coherence tomography of the optic nerve head for glaucoma detection in microdiscs.

    Science.gov (United States)

    Enders, Philip; Schaub, Friederike; Adler, Werner; Nikoluk, Roman; Hermann, Manuel M; Heindl, Ludwig M

    2017-04-01

    To assess the performance of Bruch's membrane opening (BMO)-based spectral domain optical coherence tomography (SD-OCT) of the optic nerve head for glaucoma detection in microdiscs in comparison with confocal scanning laser tomography (CSLT). Retrospective cohort study. 82 eyes of 82 patients with disc size <1.63 mm(2) underwent SD-OCT and CSLT measurements, visual field testing and clinical examination. BMO-based minimal rim width (BMO-MRW), retinal nerve fibre layer thickness (RNFLT) in SD-OCT and rim area measured in CSLT were compared and correlated with visual field defects. 51 patients with glaucoma, 11 patients with ocular hypertension (OHT) and 20 healthy controls had a mean disc area of 1.36±0.19 mm(2) in CSLT, and BMO area was 1.45±0.22 mm(2) (r=0.17; p=0.12). In patients with glaucoma, visual field mean defect was -7.5±6.7 dB. Global BMO-MRW correlated better with visual field function (Spearman's r=0.65; p<0.001) than RNFLT (r=0.58; p≤0.001) and CSLT rim area (r=0.47; p=0.004). BMO-MRW significantly deteriorated with progressive visual field loss (p<0.001). In receiver operating characteristic analysis, sensitivity of BMO-MRW was 68.6% at 95% specificity (area under curve (AUC)=0.87), similar to sensitivity of RNFLT (66.4%; AUC=0.81). Performance of CSLT rim area was significantly worse (AUC=0.70, p=0.008). In healthy controls, mean BMO-MRW was 344.3±64.1 µm, mean RNFLT 78.0±11.3 µm and CSLT mean rim area 1.07±0.18 mm(2). In small optic discs, BMO-MRW and peripapillary RNFLT (OCT) have similar sensitivity to discriminate patients with glaucoma from normal controls; both exceed CSLT rim area in diagnostic power. In glaucomatous patients, BMO-MRW correlates strongest with visual field function. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  6. Dinosaur biomechanics.

    Science.gov (United States)

    Alexander, R McNeill

    2006-08-07

    Biomechanics has made large contributions to dinosaur biology. It has enabled us to estimate both the speeds at which dinosaurs generally moved and the maximum speeds of which they may have been capable. It has told us about the range of postures they could have adopted, for locomotion and for feeding, and about the problems of blood circulation in sauropods with very long necks. It has made it possible to calculate the bite forces of predators such as Tyrannosaurus, and the stresses they imposed on its skull; and to work out the remarkable chewing mechanism of hadrosaurs. It has shown us how some dinosaurs may have produced sounds. It has enabled us to estimate the effectiveness of weapons such as the tail spines of Stegosaurus. In recent years, techniques such as computational tomography and finite element analysis, and advances in computer modelling, have brought new opportunities. Biomechanists should, however, be especially cautious in their work on animals known only as fossils. The lack of living specimens and even soft tissues oblige us to make many assumptions. It is important to be aware of the often wide ranges of uncertainty that result.

  7. Corneal Segmentation Analysis Increases Glaucoma Diagnostic Ability of Optic Nerve Head Examination, Heidelberg Retina Tomograph's Moorfield's Regression Analysis, and Glaucoma Probability Score.

    Science.gov (United States)

    Saenz-Frances, F; Jañez, L; Berrozpe-Villabona, C; Borrego-Sanz, L; Morales-Fernández, L; Acebal-Montero, A; Mendez-Hernandez, C D; Martinez-de-la-Casa, J M; Santos-Bueso, E; Garcia-Sanchez, J; Garcia-Feijoo, J

    2015-01-01

    Purpose. To study whether a corneal thickness segmentation model, consisting in a central circular zone of 1 mm radius centered at the corneal apex (zone I) and five concentric rings of 1 mm width (moving outwards: zones II to VI), could boost the diagnostic accuracy of Heidelberg Retina Tomograph's (HRT's) MRA and GPS. Material and Methods. Cross-sectional study. 121 healthy volunteers and 125 patients with primary open-angle glaucoma. Six binary multivariate logistic regression models were constructed (MOD-A1, MOD-A2, MOD-B1, MOD-B2, MOD-C1, and MOD-C2). The dependent variable was the presence of glaucoma. In MOD-A1, the predictor was the result (presence of glaucoma) of the analysis of the stereophotography of the optic nerve head (ONH). In MOD-B1 and MOD-C1, the predictor was the result of the MRA and GPS, respectively. In MOD-B2 and MOD-C2, the predictors were the same along with corneal variables: central, overall, and zones I to VI thicknesses. This scheme was reproduced for model MOD-A2 (stereophotography along with corneal variables). Models were compared using the area under the receiver operator characteristic curve (AUC). Results. MOD-A1-AUC: 0.771; MOD-A2-AUC: 0.88; MOD-B1-AUC: 0.736; MOD-B2-AUC: 0.845; MOD-C1-AUC: 0.712; MOD-C2-AUC: 0.838. Conclusion. Corneal thickness variables enhance ONH assessment and HRT's MRA and GPS diagnostic capacity.

  8. 3D Histomorphometry of the Normal and Early Glaucomatous Monkey Optic Nerve Head: Lamina Cribrosa and Peripapillary Scleral Position and Thickness

    Science.gov (United States)

    Yang, Hongli; Downs, J. Crawford; Girkin, Christopher; Sakata, Lisandro; Bellezza, Anthony; Thompson, Hilary; Burgoyne, Claude F.

    2009-01-01

    Purpose To three-dimensionally delineate the anterior and posterior surface of the lamina cribrosa, scleral flange and peripapillary sclera so as to determine the position and thickness of these structures within digital three-dimensional (3D) reconstructions of the monkey optic nerve head (ONH). Methods The trephinated ONH and peripapillary sclera from both eyes of three early glaucoma (EG) monkeys (one eye Normal, one eye given laser-induced EG) were serial-sectioned at 3-μm thickness, with the embedded tissue block face stained and imaged after each cut. Images were aligned and stacked to create 3D reconstructions, within which Bruch's membrane opening (BMO) and the anterior and posterior surfaces of the lamina cribrosa and peripapillary sclera were delineated in 40 serial, radial (4.5° interval), digital, sagittal sections. For each eye, a BMO zero reference plane was fit to the 80 BMO points, which served as the reference from which all position measurements were made. Regional laminar, scleral flange, and peripapillary scleral position and thickness were compared between the Normal and EG eyes of each monkey and between treatment groups by analysis of variance. Results Laminar thickness varies substantially within the Normal eyes and is profoundly thicker within the three EG eyes. Laminar position is permanently posteriorly deformed in all three EG eyes, with substantial differences in the magnitude and extent of deformation among them. Scleral flange and peripapillary scleral thickness vary regionally within each Normal ONH with the scleral flange and peripapillary sclera thinnest nasally. Overall, the scleral flange and peripapillary sclera immediately surrounding the ONH are posteriorly displaced relative to the more peripheral sclera. Conclusion Profound fixed posterior deformation and thickening of the lamina is accompanied by mild posterior deformation and thinning of the scleral flange and peripapillary sclera at the onset of confocal scanning laser

  9. Correlation between optic nerve head circulation and visual function before and after anti-VEGF therapy for central retinal vein occlusion: prospective, interventional case series.

    Science.gov (United States)

    Nagasato, Daisuke; Mitamura, Yoshinori; Semba, Kentaro; Akaiwa, Kei; Nagasawa, Toshihiko; Yoshizumi, Yuki; Tabuchi, Hitoshi; Kiuchi, Yoshiaki

    2016-04-05

    To determine the correlation between the optic nerve head (ONH) circulation determined by laser speckle flowgraphy and the best-corrected visual acuity or retinal sensitivity before and after intravitreal bevacizumab or ranibizumab for central retinal vein occlusion. Thirty-one eyes of 31 patients were treated with intravitreal bevacizumab or ranibizumab for macular edema due to a central retinal vein occlusion. The blood flow in the large vessels on the ONH, the best-corrected visual acuity, and retinal sensitivity were measured at the baseline, and at 1, 3, and 6 months after treatment. The arteriovenous passage time on fluorescein angiography was determined. The venous tortuosity index was calculated on color fundus photograph by dividing the length of the tortuous retinal vein by the chord length of the same segment. The blood flow was represented by the mean blur rate (MBR) determined by laser speckle flowgraphy. To exclude the influence of systemic circulation and blood flow in the ONH tissue, the corrected MBR was calculated as MBR of ONH vessel area - MBR of ONH tissue area in the affected eye divided by the vascular MBR - tissue MBR in the unaffected eye. Pearson's correlation tests were used to determine the significance of correlations between the MBR and the best-corrected visual acuity, retinal sensitivity, arteriovenous passage time, or venous tortuosity index. At the baseline, the corrected MBR was significantly correlated with the arteriovenous passage time and venous tortuosity index (r = -0.807, P retinal sensitivity at the baseline, and at 1, 3, and 6 months (all P retinal sensitivity at 6 months (r = 0.485, P = 0.005). The pre-treatment blood flow velocity of ONH can be used as a predictive factor for the best-corrected visual acuity and retinal sensitivity after anti-VEGF therapy for central retinal vein occlusion. UMIN000009072. Date of registration: 10/15/2012.

  10. Biomechanics in Schools.

    Science.gov (United States)

    Vincent, J. F. V.

    1980-01-01

    Examines current usage of the term "biomechanics" and emphasizes the importance of differentiating between structure and material. Describes current prolects in biomechanics and lists four points about the educational significance of the field. (GS)

  11. Research Techniques in Biomechanics.

    Science.gov (United States)

    Ward, Terry

    Biomechanics involves the biological human beings interacting with his/her mechanical environment. Biomechanics research is being done in connection with sport, physical education, and general motor behavior, and concerns mechanics independent of implements. Biomechanics research falls in the following two general categories: (1) that specific…

  12. 猫视乳头三维模型重建及有限元分析%Three-dimensional reconstruction and finite element analysis of the optic nerve head of a cat

    Institute of Scientific and Technical Information of China (English)

    高伟; 杨昱童; 张诗瑶; 张昆亚; 刘志成; 钱秀清

    2016-01-01

    BACKGROUND: Glaucoma is a kind of eye disease that can cause irreversible blindness which is characterized by visual field loss. Clinical research shows that the optic nerve head has changed before the visual field loss. The morphological changes of the optic nerve head have become the key to determine the early diagnosis of glaucoma and disease development. So it has important significance for us to study the morphological changes of the tissues of optic nerve head under the high intraocular pressure. OBJECTIVE: To establish three-dimensional finite element model of optic nerve head which includes choroid, retina and lamina cribrosa, and analyze the thickness of the optic nerve head under the acute high intraocular pressure. METHODS: (1) We chose healthy cats without refractive media and other eye diseases. The tomographic sequence images of the optic nerve head of a cat were obtained with the intraocular pressure of the normal value by using enhanced depth imaging spectral-domain optical coherence tomography. (2) The three-dimensional model of the retina, choroid and lamina cribrosa was obtained. Three-dimensional model of optic nerve head was established by assembling the model of the retina, the choroid and the lamina cribrosa. The thickness of the retina, choroid and lamina cribrosa was analyzed under different intraocular pressures by using the method of finite element analysis. (3) Animal model of acute ocular hypertension was established by methods of anterior chamber perfusion. The tomographic sequence images of the optic nerve head of a cat were obtained with different intraocular pressures by using enhanced depth imaging spectral-domain optical coherence tomography. Then, we measured the thickness changes of the choroid, retina and lamina cribrosa under different intraocular pressures, and compared with the results of finite element analysis. RESULTS AND CONCLUSION: The thickness of the choroid, retina and lamina cribrosa trended to be thin, and the cup

  13. HEADS UP: Sensorimotor control of the head-neck system

    NARCIS (Netherlands)

    Forbes, P.A.

    2014-01-01

    Head-neck stabilization is inherently challenging even when stationary, requiring constant vigilance to counter the downward pull of gravity. It involves a highly complex biomechanical system comprised of a large mass (the head) balanced on top of seven vertebrae (the neck), that are in turn connect

  14. Impact of intraocular pressure on changes of blood flow in the retina, choroid, and optic nerve head in rats investigated by optical microangiography.

    Science.gov (United States)

    Zhi, Zhongwei; Cepurna, William O; Johnson, Elaine C; Morrison, John C; Wang, Ruikang K

    2012-09-01

    In this paper, we demonstrate the use of optical coherence tomography/optical microangiography (OCT/OMAG) to image and measure the effects of acute intraocular pressure (IOP) elevation on retinal, choroidal and optic nerve head (ONH) perfusion in the rat eye. In the experiments, IOP was elevated from 10 to 100 mmHg in 10 mmHg increments. At each IOP level, three-dimensional data volumes were captured using an ultrahigh sensitive (UHS) OMAG scanning protocol for 3D volumetric perfusion imaging, followed by repeated B-scans for Doppler OMAG analysis to determine blood flow velocity. Velocity and vessel diameter measurements were used to calculate blood flow in selected retinal blood vessels. Choroidal perfusion was calculated by determining the peripapillary choroidal filling at each pressure level and calculating this as a percentage of area filling at baseline (10 mmHg). ONH blood perfusion was calculated as the percentage of blood flow area over a segmented ONH area to a depth 150 microns posterior to the choroidal opening. We show that volumetric blood flow reconstructions revealed detailed 3D maps, to the capillary level, of the retinal, choroidal and ONH microvasculature, revealing retinal arterioles, capillaries and veins, the choroidal opening and a consistent presence of the central retinal artery inferior to the ONH. While OCT structural images revealed a reversible compression of the ONH and vasculature with elevated IOP, OMAG successfully documented changes in retinal, choroidal and ONH blood perfusion and allowed quantitative measurements of these changes. Starting from 30 mm Hg, retinal blood flow (RBF) diminished linearly with increasing IOP and was nearly extinguished at 100 mm Hg, with full recovery after return of IOP to baseline. Choroidal filling was unaffected until IOP reached 60 mmHg, then decreased to 20% of baseline at IOP 100 mmHg, and normalized when IOP returned to baseline. A reduction in ONH blood perfusion at higher IOP's was also

  15. Heading in soccer: dangerous play?

    Science.gov (United States)

    Spiotta, Alejandro M; Bartsch, Adam J; Benzel, Edward C

    2012-01-01

    Soccer is the world's most popular sport and unique in that players use their unprotected heads to intentionally deflect, stop, or redirect the ball for both offensive and defensive strategies. Headed balls travel at high velocity pre- and postimpact. Players, coaches, parents, and physicians are justifiably concerned with soccer heading injury risk. Furthermore, risk of long-term neurocognitive and motor deficits caused by repetitively heading a soccer ball remains unknown. We review the theoretical concerns, the results of biomechanical laboratory experiments, and the available clinical data regarding the effects of chronic, subconcussive head injury during heading in soccer.

  16. FUNDAMENTALS OF BIOMECHANICS

    Directory of Open Access Journals (Sweden)

    Duane Knudson

    2007-09-01

    Full Text Available DESCRIPTION This book provides a broad and in-depth theoretical and practical description of the fundamental concepts in understanding biomechanics in the qualitative analysis of human movement. PURPOSE The aim is to bring together up-to-date biomechanical knowledge with expert application knowledge. Extensive referencing for students is also provided. FEATURES This textbook is divided into 12 chapters within four parts, including a lab activities section at the end. The division is as follows: Part 1 Introduction: 1.Introduction to biomechanics of human movement; 2.Fundamentals of biomechanics and qualitative analysis; Part 2 Biological/Structural Bases: 3.Anatomical description and its limitations; 4.Mechanics of the musculoskeletal system; Part 3 Mechanical Bases: 5.Linear and angular kinematics; 6.Linear kinetics; 7.Angular kinetics; 8.Fluid mechanics; Part 4 Application of Biomechanics in Qualitative Analysis :9.Applying biomechanics in physical education; 10.Applying biomechanics in coaching; 11.Applying biomechanics in strength and conditioning; 12.Applying biomechanics in sports medicine and rehabilitation. AUDIENCE This is an important reading for both student and educators in the medicine, sport and exercise-related fields. For the researcher and lecturer it would be a helpful guide to plan and prepare more detailed experimental designs or lecture and/or laboratory classes in exercise and sport biomechanics. ASSESSMENT The text provides a constructive fundamental resource for biomechanics, exercise and sport-related students, teachers and researchers as well as anyone interested in understanding motion. It is also very useful since being clearly written and presenting several ways of examples of the application of biomechanics to help teach and apply biomechanical variables and concepts, including sport-related ones

  17. Biomechanics principles and practices

    CERN Document Server

    Peterson, Donald R

    2014-01-01

    Presents Current Principles and ApplicationsBiomedical engineering is considered to be the most expansive of all the engineering sciences. Its function involves the direct combination of core engineering sciences as well as knowledge of nonengineering disciplines such as biology and medicine. Drawing on material from the biomechanics section of The Biomedical Engineering Handbook, Fourth Edition and utilizing the expert knowledge of respected published scientists in the application and research of biomechanics, Biomechanics: Principles and Practices discusses the latest principles and applicat

  18. Patellofemoral anatomy and biomechanics.

    Science.gov (United States)

    Sherman, Seth L; Plackis, Andreas C; Nuelle, Clayton W

    2014-07-01

    Patellofemoral disorders are common. There is a broad spectrum of disease, ranging from patellofemoral pain and instability to focal cartilage disease and arthritis. Regardless of the specific condition, abnormal anatomy and biomechanics are often the root cause of patellofemoral dysfunction. A thorough understanding of normal patellofemoral anatomy and biomechanics is critical for the treating physician. Recognizing and addressing abnormal anatomy will optimize patellofemoral biomechanics and may ultimately translate into clinical success.

  19. Developmental biomechanics of the human cervical spine.

    Science.gov (United States)

    Nuckley, David J; Linders, David R; Ching, Randal P

    2013-04-05

    Head and neck injuries, the leading cause of death for children in the U.S., are difficult to diagnose, treat, and prevent because of a critical void in our understanding of the biomechanical response of the immature cervical spine. The objective of this study was to investigate the functional and failure biomechanics of the cervical spine across multiple axes of loading throughout maturation. A correlational study design was used to examine the relationships governing spinal maturation and biomechanical flexibility curves and tolerance data using a cadaver human in vitro model. Eleven human cadaver cervical spines from across the developmental spectrum (2-28 years) were dissected into segments (C1-C2, C3-C5, and C6-C7) for biomechanical testing. Non-destructive flexibility tests were performed in tension, compression, flexion, extension, lateral bending, and axial rotation. After measuring their intact biomechanical responses, each segment group was failed in different modes to measure the tissue tolerance in tension (C1-C2), compression (C3-C5), and extension (C5-C6). Classical injury patterns were observed in all of the specimens tested. Both the functional (pcervical spine throughout maturation and elucidated age, spinal level, and mode of loading specificity. These data support our understanding of the child cervical spine from a developmental perspective and facilitate the generation of injury prevention or management schema for the mitigation of child spine injuries and their deleterious effects.

  20. Excursion of the Sciatic Nerve During Nerve Mobilization Exercises: An In Vivo Cross-sectional Study Using Dynamic Ultrasound Imaging.

    Science.gov (United States)

    Coppieters, Michel W; Andersen, Line S; Johansen, Runar; Giskegjerde, Per K; Høivik, Mona; Vestre, Siv; Nee, Robert J

    2015-10-01

    Controlled laboratory cross-sectional study using single-group, within-subject comparisons. To determine whether different types of neurodynamic techniques result in differences in longitudinal sciatic nerve excursion. Large differences in nerve biomechanics have been demonstrated for different neurodynamic techniques for the upper limb (median nerve), but recent findings for the sciatic nerve have only revealed small differences in nerve excursion that may not be clinically meaningful. High-resolution ultrasound imaging was used to quantify longitudinal sciatic nerve movement in the thigh of 15 asymptomatic participants during 6 different mobilization techniques for the sciatic nerve involving the hip and knee. Healthy volunteers were selected to demonstrate normal nerve biomechanics and to eliminate potentially confounding variables associated with dysfunction. Repeated-measures analyses of variance were used to analyze the data. The techniques resulted in markedly different amounts of nerve movement (Pmovements. Consistent with current theories and findings for the median nerve, different neurodynamic exercises for the lower limb resulted in markedly different sciatic nerve excursions. Considering the continuity of the nervous system, the movement and position of adjacent joints have a large impact on nerve biomechanics.

  1. Nerve biopsy

    Science.gov (United States)

    Biopsy - nerve ... A nerve biopsy is most often done on a nerve in the ankle, forearm, or along a rib. The health care ... feel a prick and a mild sting. The biopsy site may be sore for a few days ...

  2. Whole-head MEG analysis of cortical spatial organization from unilateral stimulation of median nerve in both hands: No complete hemispheric homology

    NARCIS (Netherlands)

    Theuvenet, Peter J.; Dijk, van Bob W.; Peters, Maria J.; Ree, van Jan M.; Lopes da Silva, Fernando L.; Chen, Andrew C.N.

    2005-01-01

    We examined the contralateral hemispheric cortical activity in MEG (151 ch) after unilateral median nerve stimulation of the right and left hand in twenty healthy right-handed subjects. The goal was to establish parameters to describe cortical activity of the hemispheric responses and to study the p

  3. Anatomy and biomechanics of the elbow joint.

    Science.gov (United States)

    Martin, Silvia; Sanchez, Eugenia

    2013-11-01

    Magnetic resonance (MR) imaging provides clinically useful information in assessing the elbow joint. Superior depiction of muscles, ligaments and tendons as well as the ability to directly visualize nerves, bone marrow and hyaline cartilage, are advantages of MR imaging relative to conventional imaging techniques. As the elbow is located superficially, clinical examination is easier for the orthopedic surgeon and only a few cases need a diagnosis for the radiologist, for this reason the elbow joint is little known for the radiologist. To better understand the injuries that occur in the elbow during the sport activities, we need a better understanding of the biomechanics of the joint. And for understanding the biomechanics, it is necessary to know the exact anatomy of the elbow joint and to be able to identify each anatomic structure in the different imaging planes and pulse sequences. This is especially important in MR as the imaging tool that shows a highest soft tissue resolution among other imaging techniques.

  4. A Review of Facial Nerve Anatomy

    OpenAIRE

    2004-01-01

    An intimate knowledge of facial nerve anatomy is critical to avoid its inadvertent injury during rhytidectomy, parotidectomy, maxillofacial fracture reduction, and almost any surgery of the head and neck. Injury to the frontal and marginal mandibular branches of the facial nerve in particular can lead to obvious clinical deficits, and areas where these nerves are particularly susceptible to injury have been designated danger zones by previous authors. Assessment of facial nerve function is no...

  5. Biomechanics of the brain

    CERN Document Server

    Miller, Karol

    2011-01-01

    With contributions from scientists at major institutions, this book presents an introduction to brain anatomy for engineers and scientists. It provides, for the first time, a comprehensive resource in the field of brain biomechanics.

  6. Computational modeling in biomechanics

    CERN Document Server

    Mofrad, Mohammad

    2010-01-01

    This book provides a glimpse of the diverse and important roles that modern computational technology is playing in various areas of biomechanics. It includes unique chapters on ab initio quantum mechanical, molecular dynamic and scale coupling methods..

  7. Gingival Recessions and Biomechanics

    DEFF Research Database (Denmark)

    Laursen, Morten Godtfredsen

    Gingival recessions and biomechanics “Tissue is the issue, but bone sets the tone.“ A tooth outside the cortical plate can result in loss of bone and development of a gingival recession. The presentation aims to show biomechanical considerations in relation to movement of teeth with gingival...... by moving the root back in the alveolus. The tooth movement is accompanied by bone gain and thus increase the success rate for soft tissue augmentation. The choice of biomechanical system influences the treatment outcome. If a standard straight wire appliance is used, a biomechanical dilemma can arise....... The forces applied to bring the tooth back into the alveolar process generate opposite reactive forces, which can direct the adjacent teeth out towards the boundary of the bony envelope. A different force system can be achieved with a segmented appliance: The reaction forces from the root movement...

  8. Biomechanically Engineered Athletes.

    Science.gov (United States)

    Perry, Tekla S.

    1991-01-01

    The real-world meeting of electronics, computer monitoring, control systems, and mathematics, introduced in the context of sports, is described. Recent advances in the field of biomechanics and its use in improving athletic performance are discussed. (KR)

  9. Identifying nonlinear biomechanical models by multicriteria analysis

    Science.gov (United States)

    Srdjevic, Zorica; Cveticanin, Livija

    2012-02-01

    In this study, the methodology developed by Srdjevic and Cveticanin (International Journal of Industrial Ergonomics 34 (2004) 307-318) for the nonbiased (objective) parameter identification of the linear biomechanical model exposed to vertical vibrations is extended to the identification of n-degree of freedom (DOF) nonlinear biomechanical models. The dynamic performance of the n-DOF nonlinear model is described in terms of response functions in the frequency domain, such as the driving-point mechanical impedance and seat-to-head transmissibility function. For randomly generated parameters of the model, nonlinear equations of motion are solved using the Runge-Kutta method. The appropriate data transformation from the time-to-frequency domain is performed by a discrete Fourier transformation. Squared deviations of the response functions from the target values are used as the model performance evaluation criteria, thus shifting the problem into the multicriteria framework. The objective weights of criteria are obtained by applying the Shannon entropy concept. The suggested methodology is programmed in Pascal and tested on a 4-DOF nonlinear lumped parameter biomechanical model. The identification process over the 2000 generated sets of parameters lasts less than 20 s. The model response obtained with the imbedded identified parameters correlates well with the target values, therefore, justifying the use of the underlying concept and the mathematical instruments and numerical tools applied. It should be noted that the identified nonlinear model has an improved accuracy of the biomechanical response compared to the accuracy of a linear model.

  10. Fundamentals of Biomechanics

    OpenAIRE

    Duane Knudson

    2007-01-01

    DESCRIPTION This book provides a broad and in-depth theoretical and practical description of the fundamental concepts in understanding biomechanics in the qualitative analysis of human movement. PURPOSE The aim is to bring together up-to-date biomechanical knowledge with expert application knowledge. Extensive referencing for students is also provided. FEATURES This textbook is divided into 12 chapters within four parts, including a lab activities section at the end. The division is as follow...

  11. Role of the vegus nerve in epilepsy (image)

    Science.gov (United States)

    The vagus nerves branch off the brain on either side of the head and travel down the neck, along the ... the body, and affect swallowing and speech. The vagus nerves also connect to parts of the brain involved ...

  12. Application of short-segment nerve conduction studies in the entrapment of the peroneal nerve across the fibular head%短节段神经传导检测法在腓总神经腓骨小头部位嵌压性损伤中的应用价值

    Institute of Scientific and Technical Information of China (English)

    左星; 张蓓; 林涛; 高瑛; 徐堂辉; 王丹; 李亚军

    2016-01-01

    Objective To evaluate the usefulness of the short-segment nerve conduction studies (SSCSs,inching test) of the peroneal nerve across the fibular head in order to diagnose and localize the site of entrapment of the nerve.Methods Fifty-four patients with suspected peroneal nerve palsy and 30 controls were studied.The symptoms all occurred in unilateral leg,involving 25 left legs and 29 right legs.Both long segment motor nerve conduction studies (LSMCs) and SSCSs were performed in all patients and controls.SSCSs were obtained at 2 cm intervals,starting 6 cm proximal (P6,P4 and P2) and 4 cm distal (D2 and D4) ending to the fibular head prominence (P).Results When nerve conduction of the entire 10 cm segment across the fibular head was tested by the conventional method,only 40 showed reduction in amplitude or slowing of motor conduction velocity or both.However,with SSCSs,54 peroneal nerves were all discovered abnormal.The results of comparison of conventional methods suggested that there were significant differences in conduction velocity between the fibular head-Ankle segment and the knee-fibular head segment in the case group,the latter ((33.63 ± 9.29) m/s) being slower than the former ((47.92 ± 4.04) m/s;t =9.776,P =0.000),while there was no obvious abnormality in the control group.The results of the control group detected by SSCSs showed that there was no significant difference between the left and right sides of the mean amplitude of the stimulation points and the mean time of segmental nerve conduction.Therefore,we set the exception criteria as the segmental nerve conduction time is longer than the corresponding control group (i + 2 s),and the CMAP amplitude of proximal stimulation point decreased by more than 20% than the adjacent distal segment.In accordance with this standard,we found that the lesions were located in P6 to P4 in 2/54 (3.7%) legs,P4 to P2 in 4/54 (7.4%) legs,P2 to P in 43/54 (79.6%) legs,P to D2 in 12/54 (22.2%) legs,D2 to D4 in 3

  13. Qualitative Biomechanics and the Tennis Ground Strokes. Revised

    Science.gov (United States)

    Errington, Joseph

    This tennis stroke analysis, based on the application of biomechanic principles, is designed to help those who play tennis only once or twice a week. It is noted that, because the tennis player has a limited power potential, the only way to increase his racket head speed is to rotate his body. The mechanics of tennis are discussed by dividing it…

  14. Corneal biomechanics: a review.

    Science.gov (United States)

    Piñero, David P; Alcón, Natividad

    2015-03-01

    Biomechanics is often defined as 'mechanics applied to biology'. Due to the variety and complexity of the behaviour of biological structures and materials, biomechanics is better defined as the development, extension and application of mechanics for a better understanding of physiology and physiopathology and consequently for a better diagnosis and treatment of disease and injury. Different methods for the characterisation of corneal biomechanics are reviewed in detail, including those that are currently commercially available (Ocular Response Analyzer and CorVis ST). The clinical applicability of the parameters provided by these devices are discussed, especially in the fields of glaucoma, detection of ectatic disorders and orthokeratology. Likewise, other methods are also reviewed, such as Brillouin microscopy or dynamic optical coherence tomography and others with potential application to clinical practice but not validated for in vivo measurements, such as ultrasonic elastography. Advantages and disadvantages of all these techniques are described. Finally, the concept of biomechanical modelling is revised as well as the requirements for developing biomechanical models, with special emphasis on finite element modelling.

  15. Biomechanical origin of the Denonvilliers' fascia.

    Science.gov (United States)

    Bertrand, M M; Alsaid, B; Droupy, S; Benoit, G; Prudhomme, M

    2014-01-01

    Since 1836 and the first description of the recto-genital fascia by Charles Denonvilliers, many anatomists have shown interest in this subject. Recently, pelvic surgeons have in turn shown similar interest, for they consider that perfect knowledge of this anatomical domain is crucial for optimal nerve conservation during surgery. Thanks to new anatomical description techniques, fascia location and relationships with pelvic nerves now appear clearer. To describe and represent Denonvilliers' fascia and its relationships in the female foetus at different stages of gestation and in three-dimensional space (3D). Computer-assisted anatomical dissection technique was used. Serial histological sections were made from four human female foetuses. Sections were treated with conventional staining, as well as with nerve and smooth muscle immunostaining. Finally, the sections were digitalized and reconstructed in 3D. Denonvilliers' fascia was clearly located and visualized in three dimensions. It was present in the female foetus, being distinct from the fascia propria of the rectum. It appeared to be composed of multiple parallel layers situated between the vagina and the rectum. From a lateral view, it had an asymmetrical "Y-shaped" aspect that seemed to play the role of a protective sheet for the neurovascular bundles. This study betters our comprehension of the Denonvilliers' fascia in the female foetus and of its connections with pelvic nerves. It also provides a better understanding of safe planes during pelvic dissection. These findings also suggest a biomechanical theory for embryological origin of the Denonvilliers' fascia.

  16. Biomechanical characteristics of bipolar femoral head prosthesis replacement and internal fixation for femoral neck fractures in the elderly%股骨头双极假体置换及内固定修复老年股骨颈骨折的生物力学特征

    Institute of Scientific and Technical Information of China (English)

    姜源涛; 焦建宝; 薛金伟; 王云飞

    2016-01-01

    背景:双极人工股骨头假体在股骨颈骨折患者中虽然能够取得理想的修复效果,但是临床上对于双极人工股骨头假体的生物力学性能尚存在较大的争议。目的:比较股骨头双极假体置换及内固定修复老年股骨颈骨折的生物力学性能。方法:选取23具(46侧)老年股骨颈骨折股骨标本进行分析,随机将标本分为内固定组和股骨头双极假体置换组,每组23侧。内固定组标本行常规金属植入物内固定,股骨头双极假体置换组行股骨头双极假体置换。在万能试验机上测定股骨假体柄的力学性能,比较股骨头双极假体置换及内固定的生物力学性能。结果与结论:①股骨头双极假体置换组的最大承载负荷显著高于内固定组(P<0.05);最大承载负荷趋势图显示,股骨头双极假体置换组最大承载负荷显著高于内固定组(P<0.05);②股骨头双极假体置换组轴向拔出试验位移显著短于内固定组(P<0.05);轴向拔出试验位移趋势图显示,股骨头双极假体置换组轴向拔出试验位移显著短于内固定组(P<0.05);③结果提示,与内固定植入物相比,股骨头双极假体置换修复老年股骨颈骨折更加稳定,修复效果更佳,能够提高患者髋关节功能,获得良好的初始稳定性。%BACKGROUND:Bipolar femoral head prosthesis has achieved the desired repair effect in patients with femoral neck fracture, but there is stil much controversy on the biomechanical properties of bipolar artificial femoral head prosthesis. OBJECTIVE:To compare biomechanical properties of the bipolar femoral head prosthesis replacement and internal fixation in the repair of femoral neck fracture in the elderly. METHODS:Twenty-three (46 sides) senile femoral neck fracture specimens were analyzed and randomized into internal fixation group(n=23)and bipolar femoral head prosthesis replacement group (n=23). Specimens in the internal

  17. Clinico-embryological perspective of a rare accessory brachial muscle with possible musculocutaneous nerve compression.

    Science.gov (United States)

    Mehta, V; Yadav, Y; Arora, Jyoti; Kumar, H; Suri, R K; Rath, G

    2009-03-01

    Both brachialis and biceps brachii are primary flexors of the arm and elbow from the biomechanical perspective. Numerous reports exist in anatomical literature regarding accessory heads of biceps brachii, although such accessory bellies in relation to brachialis muscle are less frequently elucidated. We report a unilateral case of a rare accessory muscle interposed between the biceps brachii and brachialis, having the musculocutaneous nerve (MCN) entrapped between the two. Furthermore, the muscle divided into two slips, upper slip was attached to biceps brachii and the other gained insertion to the brachial fascia. Innervation to this accessory muscle was derived from MCN. The embryological basis for such supernumerary muscle is discussed. Additionally, the case is considered under surgical and clinical perspective, highlighting the importance of familiarity with such variations. Anatomical variations of the brachial musculature may cause diagnostic perplexities while interpreting MRI or CT scans.

  18. Transverse Ultrasound Assessment of Median Nerve Deformation and Displacement in the Human Carpal Tunnel during Wrist Movements

    OpenAIRE

    2013-01-01

    The symptoms of carpal tunnel syndrome, a compression neuropathy of the median nerve at the wrist, are aggravated by wrist motion, but the effect of these motions on median nerve motion are unknown. In order to better understand the biomechanics of the abnormal nerve, it is first necessary to understand normal nerve movement. The purpose of this study was to evaluate the deformation and displacement of the normal median nerve at the proximal carpal tunnel level on transverse ultrasound images...

  19. Gingival Recessions and Biomechanics

    DEFF Research Database (Denmark)

    Laursen, Morten Godtfredsen

    Gingival recessions and biomechanics “Tissue is the issue, but bone sets the tone.“ A tooth outside the cortical plate can result in loss of bone and development of a gingival recession. The presentation aims to show biomechanical considerations in relation to movement of teeth with gingival...... recessions. Gingival recession is a problem often in the region of the lower incisors. A micro-CT study on human autopsy material, performed at the University of Aarhus, confirmed that the anterior mandibular alveolar envelope is indeed very thin. The prognosis of a gingival recession can be improved...

  20. Effect of FUYANG HUOGU(复阳活骨)pill combined with core decompression on the intraosseous pressure within the femoral head and biomechanical parameter for the model with steroid induced avascular necrosis of femoral head%复阳活骨丸配合髓芯减压术对激素性股骨头坏死模型股骨头骨内压及生物力学的影响

    Institute of Scientific and Technical Information of China (English)

    廖宏伟; 张建福; 陈献韬

    2011-01-01

    目的:观察复阳活骨丸配合髓芯减压术对激素性股骨头缺血坏死家兔模型股骨头骨内压和生物力学性能的影响,探讨其防治股骨头缺血性坏死的可能机制,为该方法的临床应用提供依据.方法:将45只健康家兔随机分为正常对照组(A组)、模型对照组(B组)、复阳活骨丸组(C组)、髓芯减压组(D组)、复阳活骨丸+髓芯减压组(E组).除A组外,其余各组家兔建立激素性股骨头坏死模型.造模成功后,A、B两组不作治疗,C组采用复阳活骨丸灌胃治疗,D组行髓芯减压术治疗,E组采用复阳活骨丸灌胃加髓芯减压术治疗.治疗6周后测定各组家兔股骨头骨内压,并检测股骨头生物力学参数.结果:各组股骨头骨内压比较,差异有统计学意义(F=7.894,P=0.000);组间两两比较,B、C组均高于A组(LSD-t=10.284,P=0.000;LSD-t=8.356,P=0.000),D、E组与A组比较差异无统计学意义(LSD-t=0.574,P=0.683;LSD-t=0.654,P=0.725);C、D、E组均低于B组(LSD-t=-4.232.P=0.015;LSD-t=-5.241,P=0.000;LSD-t=-6.766,P=0.000);C组高于D、E组(LSD-t=3.876,P=0.027:LSD-t=4.031,P=0.013);D组与E组比较差异无统计学意义(LSD-t=0.562,P=0.939).生物力学指标测定,B组骨强度、骨刚度、弹性模量、破裂强度等均呈现骨质疏松表现,C、D、E组上述指标均有所改善,且E组改善优于C、D两组.结论:复阳活骨丸配合髓芯减压术可有效治疗激素性股骨头缺血坏死.其可能机制为改善股骨头内微循环,扭转股骨头缺血状态,促进骨小梁修复,降低骨内压,提高骨强度,阻止股骨头变形,从而达到治疗股骨头缺血性坏死的目的.%Objective:To observe the effect of FUYANG HUOGU ( 复 阳 活 骨)pill combined with core decompression on the intraosseous pressure within the femoral head and biomechanical parameters for the rabbit model with steroid induced avascular necrosis of femoral head(SANFH).Methods:45 healthy rabbits were randomly divided into normal

  1. Nerve conduction and electromyography studies.

    Science.gov (United States)

    Kane, N M; Oware, A

    2012-07-01

    Nerve conduction studies (NCS) and electromyography (EMG), often shortened to 'EMGs', are a useful adjunct to clinical examination of the peripheral nervous system and striated skeletal muscle. NCS provide an efficient and rapid method of quantifying nerve conduction velocity (CV) and the amplitude of both sensory nerve action potentials (SNAPs) and compound motor action potentials (cMAPs). The CV reflects speed of propagation of action potentials, by saltatory conduction, along large myelinated axons in a peripheral nerve. The amplitude of SNAPs is in part determined by the number of axons in a sensory nerve, whilst amplitude of cMAPs reflects integrated function of the motor axons, neuromuscular junction and striated muscle. Repetitive nerve stimulation (RNS) can identify defects of neuromuscular junction (NMJ) transmission, pre- or post-synaptic. Needle EMG examination can detect myopathic changes in muscle and signs of denervation. Combinations of these procedures can establish if motor and/or sensory nerve cell bodies or peripheral nerves are damaged (e.g. motor neuronopathy, sensory ganglionopathy or neuropathy), and also indicate if the primary target is the axon or the myelin sheath (i.e. axonal or demyelinating neuropathies). The distribution of nerve damage can be determined as either generalised, multifocal (mononeuropathy multiplex) or focal. The latter often due to compression at the common entrapment sites (such as the carpal tunnel, Guyon's canal, cubital tunnel, radial groove, fibular head and tarsal tunnel, to name but a few of the reported hundred or so 'entrapment neuropathies').

  2. Shoulder posture and median nerve sliding

    Directory of Open Access Journals (Sweden)

    Dilley Andrew

    2004-07-01

    Full Text Available Abstract Background Patients with upper limb pain often have a slumped sitting position and poor shoulder posture. Pain could be due to poor posture causing mechanical changes (stretch; local pressure that in turn affect the function of major limb nerves (e.g. median nerve. This study examines (1 whether the individual components of slumped sitting (forward head position, trunk flexion and shoulder protraction cause median nerve stretch and (2 whether shoulder protraction restricts normal nerve movements. Methods Longitudinal nerve movement was measured using frame-by-frame cross-correlation analysis from high frequency ultrasound images during individual components of slumped sitting. The effects of protraction on nerve movement through the shoulder region were investigated by examining nerve movement in the arm in response to contralateral neck side flexion. Results Neither moving the head forward or trunk flexion caused significant movement of the median nerve. In contrast, 4.3 mm of movement, adding 0.7% strain, occurred in the forearm during shoulder protraction. A delay in movement at the start of protraction and straightening of the nerve trunk provided evidence of unloading with the shoulder flexed and elbow extended and the scapulothoracic joint in neutral. There was a 60% reduction in nerve movement in the arm during contralateral neck side flexion when the shoulder was protracted compared to scapulothoracic neutral. Conclusion Slumped sitting is unlikely to increase nerve strain sufficient to cause changes to nerve function. However, shoulder protraction may place the median nerve at risk of injury, since nerve movement is reduced through the shoulder region when the shoulder is protracted and other joints are moved. Both altered nerve dynamics in response to moving other joints and local changes to blood supply may adversely affect nerve function and increase the risk of developing upper quadrant pain.

  3. A mouse ocular explant model that enables the study of living optic nerve head events after acute and chronic intraocular pressure elevation: Focusing on retinal ganglion cell axons and mitochondria.

    Science.gov (United States)

    Kimball, Elizabeth C; Pease, Mary E; Steinhart, Matthew R; Oglesby, Ericka N; Pitha, Ian; Nguyen, Cathy; Quigley, Harry A

    2017-07-01

    We developed an explant model of the mouse eye and optic nerve that facilitates the study of retinal ganglion cell axons and mitochondria in the living optic nerve head (ONH) in an ex vivo environment. Two transgenic mouse strains were used, one expressing yellow fluorescent protein in selected axons and a second strain expressing cyan fluorescent protein in all mitochondria. We viewed an explanted mouse eye and optic nerve by laser scanning microscopy at and behind the ONH, the site of glaucoma injury. Explants from previously untreated mice were studied with the intraocular pressure (IOP) set artificially at normal or elevated levels for several hours. Explants were also studied from eyes that had undergone chronic IOP elevation from 14 h to 6 weeks prior to ex vivo study. Image analysis in static images and video of individual mitochondria or axonal structure determined effects of acute and chronic IOP elevation. At normal IOP, fluorescent axonal structure was stable for up to 3 h under ex vivo conditions. After chronic IOP elevation, axonal integrity index values indicated fragmentation of axon structure in the ONH. In mice with fluorescent mitochondria, the normal density decreased with distance behind the ONH by 45% (p = 0.002, t-test). Density increased with prior chronic IOP elevation to 21,300 ± 4176 mitochondria/mm(2) compared to control 16,110 ± 3159 mitochondria/mm(2) (p = 0.025, t-test), but did not increase significantly after 4 h, acute IOP elevation (1.5% decrease in density, p = 0.83, t-test). Mean normal mitochondrial length of 2.3 ± 1.4 μm became 13% smaller after 4 h of IOP elevation ex vivo compared to baseline (p = 0.015, t-test, N-10). Normal mitochondrial speed of movement was significantly slower in the anterograde direction (towards the brain) than retrograde, but there were more mitochondria in motion and traveling longer lengths in anterograde direction. The percent of mitochondria in motion decreased by >50

  4. 股骨头内撑器的研制及其治疗股骨头缺血性坏死的生物力学研究%The development and biomechanical study of interior maintaining system for treatment of avascular necrosis in femoral head

    Institute of Scientific and Technical Information of China (English)

    李康华; 肖东民; 高曙光; 李雄; 雷光华

    2011-01-01

    目的 探讨一种新型股骨头内撑器对股骨头颈生物力学的影响,为股骨头缺血性坏死提供一种新的治疗方法.方法 根据股骨头、颈的解剖特点和生物力学原理,设计制造股骨头内撑器.取正常成人股骨上段标本15具,随机分为3组,正常对照组(A组);减压植骨组(B组),于股骨外侧粗隆下沿股骨中心至股骨头软骨下0.5 cm钻一直径1 cm 隧道,用刮匙将股骨头软骨下刮出一直径约2 cm空间,然后进行植骨;内撑器植骨组(C组),按照B组先制造股骨头颈隧道及扩大股骨头软骨下空间,然后安装内撑器、植骨.采用力学实验机在股骨头顶部逐级加载至股骨毁损,分别记录并比较股骨转子窝部、股骨距、股骨大转子下的应变,股骨头塌陷和股骨头颈损毁时的最大载荷.结果 300 N载荷时,股骨转子窝部及股骨矩应变:A组和C组均大于B组,A组和C组之间无统计学差异.股骨转子下应变:A组小于B、C组,C组小于B组.应变组间比较:A组股骨转子窝部与股骨矩无统计学差异,均大于股骨转子下;B组股骨转子窝部与股骨矩无统计学差异,均小于股骨转子下;C组股骨转子窝部与股骨矩无统计学差异,均小于股骨转子下.各组股骨头塌陷和股骨头颈损毁的最大载荷:B组小于A、C组,A组和C组无统计学差异.以上结果显示,正常情况下应力集中于股骨转子窝部和股骨距,减压植骨后应力则集中于股骨转子下,承载负荷明显低于正常,置入内撑器并植骨后其应力分布及承载负荷均接近正常.结论股骨头内撑器加植骨能有效地维持股骨头颈的生物力学性能,为该方法的临床应用提供了生物力学依据.%Objective To develope a new type of femoral head interior supporting system for the treatment of femoral head osteonecrosis and evaluate its biomechanical efficacy. Methods The new type of femoral head interior supporting system was designed according to

  5. Mathematical foundations of biomechanics.

    Science.gov (United States)

    Niederer, Peter F

    2010-01-01

    The aim of biomechanics is the analysis of the structure and function of humans, animals, and plants by means of the methods of mechanics. Its foundations are in particular embedded in mathematics, physics, and informatics. Due to the inherent multidisciplinary character deriving from its aim, biomechanics has numerous connections and overlapping areas with biology, biochemistry, physiology, and pathophysiology, along with clinical medicine, so its range is enormously wide. This treatise is mainly meant to serve as an introduction and overview for readers and students who intend to acquire a basic understanding of the mathematical principles and mechanics that constitute the foundation of biomechanics; accordingly, its contents are limited to basic theoretical principles of general validity and long-range significance. Selected examples are included that are representative for the problems treated in biomechanics. Although ultimate mathematical generality is not in the foreground, an attempt is made to derive the theory from basic principles. A concise and systematic formulation is thereby intended with the aim that the reader is provided with a working knowledge. It is assumed that he or she is familiar with the principles of calculus, vector analysis, and linear algebra.

  6. Transverse ultrasound assessment of median nerve deformation and displacement in the human carpal tunnel during wrist movements

    NARCIS (Netherlands)

    Y. Wang (Yuexiang); C. Zhao; S.M. Passe (Sandra); A. Filius (Anika); A.R. Thoreson (Andrew); P. An (Ping); P.C. Amadio (Peter )

    2014-01-01

    textabstractThe symptoms of carpal tunnel syndrome, a compression neuropathy of the median nerve at the wrist, are aggravated by wrist motion, but the effect of these motions on median nerve motion are unknown. To better understand the biomechanics of the abnormal nerve, it is first necessary to und

  7. Transverse ultrasound assessment of median nerve deformation and displacement in the human carpal tunnel during wrist movements

    NARCIS (Netherlands)

    Y. Wang (Yuexiang); C. Zhao; S.M. Passe (Sandra); A. Filius (Anika); A.R. Thoreson (Andrew); P. An (Ping); P.C. Amadio (Peter )

    2014-01-01

    textabstractThe symptoms of carpal tunnel syndrome, a compression neuropathy of the median nerve at the wrist, are aggravated by wrist motion, but the effect of these motions on median nerve motion are unknown. To better understand the biomechanics of the abnormal nerve, it is first necessary to und

  8. Interpreting & Biomechanics. PEPNet Tipsheet

    Science.gov (United States)

    PEPNet-Northeast, 2001

    2001-01-01

    Cumulative trauma disorder (CTD) refers to a collection of disorders associated with nerves, muscles, tendons, bones, and the neurovascular (nerves and related blood vessels) system. CTD symptoms may involve the neck, back, shoulders, arms, wrists, or hands. Interpreters with CTD may experience a variety of symptoms including: pain, joint…

  9. Ulnar head replacement.

    Science.gov (United States)

    Herbert, Timothy J; van Schoonhoven, Joerg

    2007-03-01

    Recent years have seen an increasing awareness of the anatomical and biomechanical significance of the distal radioulnar joint (DRUJ). With this has come a more critical approach to surgical management of DRUJ disorders and a realization that all forms of "excision arthroplasty" can only restore forearm rotation at the expense of forearm stability. This, in turn, has led to renewed interest in prosthetic replacement of the ulnar head, a procedure that had previously fallen into disrepute because of material failures with early implants, in particular, the Swanson silicone ulnar head replacement. In response to these early failures, a new prosthesis was developed in the early 1990s, using materials designed to withstand the loads across the DRUJ associated with normal functional use of the upper limb. Released onto the market in 1995 (Herbert ulnar head prosthesis), clinical experience during the last 10 years has shown that this prosthesis is able to restore forearm function after ulnar head excision and that the materials (ceramic head and noncemented titanium stem), even with normal use of the limb, are showing no signs of failure in the medium to long term. As experience with the use of an ulnar head prosthesis grows, so does its acceptance as a viable and attractive alternative to more traditional operations, such as the Darrach and Sauve-Kapandji procedures. This article discusses the current indications and contraindications for ulnar head replacement and details the surgical procedure, rehabilitation, and likely outcomes.

  10. Prediction of Short-Term Outcome in Acute Superior Vestibular Nerve Failure: Three-Dimensional Video-Head-Impulse Test and Caloric Irrigation

    Directory of Open Access Journals (Sweden)

    Holger A. Rambold

    2015-01-01

    Full Text Available This retrospective study examines acute unilateral vestibular failure (up to seven days after onset with modern vestibular testing (caloric irrigation and video-head-impulse test, vHIT in 54 patients in order to test if the short-term outcome of the patients depends on the lesion pattern defined by the two tests. Patients were grouped according to a pathological unilateral caloric weakness without a pathological vHIT: group I; additional a pathological vHIT of the lateral semicircular canal (SCC: group II; and an additional pathological vHIT of the anterior SCC: group III. Patients with involvement of the posterior SCC were less frequent and not included in the analysis. Basic parameters, such as age of the subjects, days after symptom onset, gender, side of the lesion, treatment, and dizziness handicap inventory, were not different in groups I to III. The frequency of pathological clinical findings and pathological quantified measurements increased from groups I to III. The outcome parameter “days spent in the hospital” was significantly higher in group III compared to group I. The analysis shows that differential vestibular testing predicts short-term outcome of the patients and might be in future important to treat and coach patients with vestibular failure.

  11. 髋关节表面置换术中股骨头缺损区骨水泥填充和空置两种处理方法的生物力学比较%Biomechanical comparison of bone-cement filling and cement vacancy treatments for femoral head defect in hip resurfacing arthroplasty

    Institute of Scientific and Technical Information of China (English)

    何志勇; 李明; 陶崑; 方超华; 章军辉; 狄正林

    2014-01-01

    Objective To investigate the reliable treatment methods for the femoral head defect during the hip resurfacing arthroplasty,by comparing the biomechanical effects between bone cement filling and cement vacancy using three-dimensional (3-D) finite element analysis.Methods The 3-D finite element model of the normal femur was constructed based on the CT scanning.Four defect models were established by the computer assissted design technology.The defect diameter was 50%of the femoral head diameter in two models, and it was 80%of the femoral head diameter in the other two models.The femoral head defects were dealt with cement filling or vacancy.The models were loaded with the simulated standing stress, and the biomechanical indices of the femoral head and neck were compared and analyzed, including the stress peak and the equivalent strain.Results The stress concentration in the femoral head: in the model of 50%diameter defect, the stress concentration was not significant in the cement filling group, but it was significant in areaⅠof the femoral head in the vacancy group;in the model of 80%diameter defect filled with cement, the stress concentration exceeded 100% in area Ⅰ of the femoral head, while in the vacancy group, it exceeded 1000%in areaⅠ;the maximum stress concentration in areaⅡwas as high as 766.89%.The stress concentration in the femoral neck:in the model of 50% diameter defect, the stress concentration in the femoral neck was between -50% and 50% in both groups;in the model of 80%diameter defect, it was between -50% and 50% in the cement filling group, while it was extremely increased in the vacancy group.The equivalent strain in the femoral head:in the model of 50% diameter defect, the equivalent strain did not chang significantly in the cement filling group, while it increased significantly in the proximal part of the head in the vacancy group;in the model of 80%diameter defect, it increased significantly in the vacancy group.The equivalent strain in

  12. A review of facial nerve anatomy.

    Science.gov (United States)

    Myckatyn, Terence M; Mackinnon, Susan E

    2004-02-01

    An intimate knowledge of facial nerve anatomy is critical to avoid its inadvertent injury during rhytidectomy, parotidectomy, maxillofacial fracture reduction, and almost any surgery of the head and neck. Injury to the frontal and marginal mandibular branches of the facial nerve in particular can lead to obvious clinical deficits, and areas where these nerves are particularly susceptible to injury have been designated danger zones by previous authors. Assessment of facial nerve function is not limited to its extratemporal anatomy, however, as many clinical deficits originate within its intratemporal and intracranial components. Similarly, the facial nerve cannot be considered an exclusively motor nerve given its contributions to taste, auricular sensation, sympathetic input to the middle meningeal artery, and parasympathetic innervation to the lacrimal, submandibular, and sublingual glands. The constellation of deficits resulting from facial nerve injury is correlated with its complex anatomy to help establish the level of injury, predict recovery, and guide surgical management.

  13. Biomechanics of Rowing

    Science.gov (United States)

    Hase, Kazunori; Kaya, Motoshi; Yamazaki, Nobutoshi; Andrews, Brian J.; Zavatsky, Amy B.; Halliday, Suzanne E.

    Compared with the other exercise, such as walking and cycling, rowing was expected to have some fitness advantage, while there were some misgivings about the risk of injury. The objectives of this study were to quantify biomechanical characteristics of rowing for fitness and rehabilitation and to offer normative data for the prevention of injury and for determining effective exercise. An experiment was performed to collect the kinematic and kinetic data during rowing by experienced and non-experienced subjects. A three-dimensional whole-body musculo-skeletal model was used to calculate the biomechanical loads, such as the joint moments, the muscular tensions, the joint contact forces and the energy consumption. The results of this study indicate that rowing is an effective exercise for rehabilitation and fitness. However, the non-experienced rower should acquire considerable skill to obtain sufficient exercise. The rowing cadence should be decided according to the purpose of the exercise.

  14. 肱骨头内翻畸形导致肱骨近端骨折内固定失败的生物力学研究%Biomechanical study of failed internal fixation for proximal humerus fractures caused by varus deformity of humeral head

    Institute of Scientific and Technical Information of China (English)

    白露; 张洪雷; 陈鹏; 李伟; 江长青; 张文涛

    2015-01-01

    Background Proximal humerus fracture (PHF ) is a common disease in the traumatic orthopedics due to decreased density of bone in the proximal humerus with age .It occurs more often in the medium‐and old‐age people ,accounting for 5% of fractures .With the process of aging population ,the incidence of PHF tends to increase .In recent 20 years ,the surgery methods of unstable PHF change greatly from the percutaneous fixation and common plate for fractures to locking plate fixation with "internal fixator" as mainstay .As the locking plate is widely used for PHF ,some medium‐and long‐term clinical follow‐up data indicated loss of reduction of fracture ,varus deformity of humeral head ,and secondary internal fixation failure were found in PHF cases with two or three sites of defective medial cortex .These complications are characterized by defective medial cortex and varus deformity of humeral head .Over time ,it causes varus and prolapsed of humeral head ,breakage of screws or plate .From biomechanics ,the loss of support for proximal humerus by the medial cortex is an unstable factor .But not all cases with defective medial cortex develop internal fixation failure .The types of internal fixation failure vary in patients .Is the varus deformity of humerus head another risk factor for internal fixation failure? This study investigated the relationship between the varus deformity of humeral head and the internal fixation failures after locking plate treatment for PHF from the biomechanics .Methods Sample treatment and establishment of fracture model:6 pairs of adult humeral samples with antiseptic treatment were obtained from the anatomy department of the Shenzhen University‐affiliated Medical School .The pathological symptoms such as bone disease and chronic fracture were excluded by radiograph .The samples were stored at -20 ℃ before biomechanical study and thawed at room temperature (18 ℃) for 8 h when the biomechanical study was about to start

  15. Clinical implications of the surgical anatomy of the sural nerve.

    Science.gov (United States)

    Coert, J H; Dellon, A L

    1994-11-01

    The exact anatomy of the sural nerve remains important for many clinical situations. To better understand this anatomy, 25 embalmed and 10 fresh cadaver pairs were studied. The origin of the common sural nerve in relation to the fibular head and its medial and lateral sural components were investigated. The lateral sural nerve was absent in 4 percent of the embalmed cadavers. The lateral and medial sural nerves united in the popliteal fossa in 12 percent and in the lower third of the leg in 84 percent of the cadavers. A site was identified where the lateral sural and lateral cutaneous nerve of the calf pierced the deep fascia. This site was centered about the fibular head and may be viewed as a potential site of nerve compression. There is application of these findings to nerve grafting, neuroma prevention and treatment, and sural nerve biopsy.

  16. The biomechanics of soccer: a review.

    Science.gov (United States)

    Lees, A; Nolan, L

    1998-04-01

    surface types over a period of several games. Therefore, changing from one surface to another is a major aetiological factor in surface-related injuries. Heading the ball could lead to long-term brain damage. Simulation studies suggest the importance of ball mass, ball speed and player mass in affecting the severity of impact. Careful instruction and skill development, together with the correct equipment, is necessary for young players. Most applications of biomechanical techniques to soccer have been descriptive experimental studies. Biomechanical modelling techniques have helped in the understanding of the underlying mechanisms of performance, although their use has been limited. It is concluded that there are still many features of the game of soccer that are amenable to biomechanical treatment, and many opportunities for biomechanists to make a contribution to the science of soccer.

  17. Biomechanics of injury prediction for anthropomorphic manikins - preliminary design considerations

    Energy Technology Data Exchange (ETDEWEB)

    Engin, A.E. [Univ. of South Alabama, Mobile, AL (United States)

    1996-12-31

    The anthropomorphic manikins are used in automobile safety research as well as in aerospace related applications. There is now a strong need to advance the biomechanics knowledge to determine appropriate criteria for injury likelihood prediction as functions of manikin-measured responses. In this paper, three regions of a manikin, namely, the head, knee joint, and lumbar spine are taken as examples to introduce preliminary design considerations for injury prediction by means of responses of theoretical models and strategically placed sensing devices.

  18. Supernumerary head of biceps brachii

    OpenAIRE

    Balasubramanian A

    2010-01-01

    The biceps brachii muscle and the musculocutaneous nerve of arm are frequent in their variations. A third head of biceps brachii was noted unilaterally during routine anatomy dissection. Variation in musculocutaneous nerve was also seen on the same arm. The evolutionary and functional basis of such variations are discussed. Such variations become relevant during surgical intervention of the arm, especially after humeral fracture with subsequent unusual bone displacements.

  19. Supernumerary head of biceps brachii

    Directory of Open Access Journals (Sweden)

    Balasubramanian A

    2010-12-01

    Full Text Available The biceps brachii muscle and the musculocutaneous nerve of arm are frequent in their variations. A third head of biceps brachii was noted unilaterally during routine anatomy dissection. Variation in musculocutaneous nerve was also seen on the same arm. The evolutionary and functional basis of such variations are discussed. Such variations become relevant during surgical intervention of the arm, especially after humeral fracture with subsequent unusual bone displacements.

  20. Biomecânica de quatro técnicas de fixação da fratura em quatro partes da cabeça umeral Biomechanics of four techniques for fixation of the four-part humeral head fracture

    Directory of Open Access Journals (Sweden)

    Elpídio da Graça

    2013-02-01

    Full Text Available OBJETIVO: Realizar um estudo biomecânico de quatro técnicas de fixação das fraturas em quatro partes da cabeça umeral. MÉTODOS: A fratura foi reproduzida em 40 úmeros plásticos, divididos em grupos de dez conforme a técnica de fixação, cada uma delas empregando diferentes recursos de fixação, em configurações distintas. Os modelos umerais foram montados em uma escápula de alumínio, com tiras de couro mimetizando os tendões do capuz rotador, e submetidos a ensaios de encurvamento e de torção em uma máquina universal de ensaios, usando a rigidez relativa como parâmetro de avaliação. Montagens com o úmero intacto foram analisadas para comparação. RESULTADOS: O comportamento biomecânico das técnicas de fixação variou dentro de uma ampla faixa, as montagens incluindo a placa DCP e os parafusos de 4,5mm de diâmetro sendo significantemente mais rígidos do que as montagens com os fios de Kirschner e os parafusos 3,5 mm de diâmetro. CONCLUSÃO: As quatro técnicas foram capazes de suportar cargas compatíveis com a demanda fisiológica, mas aquelas com a maior rigidez relativa devem ser as preferidas para finalidades clínicas. Trabalho experimental.OBJECTIVE: To carry out a biomechanical study of four techniques for fixation of four-part humeral head fractures. METHODS: The fracture was reproduced in 40 plastic humeri, divided into groups of ten according to the fixation technique, each one employing different fixation resources, in different configurations. The humeral models were mounted on an aluminum scapula, with leather straps simulating the rotator cuff tendons, and submitted to bending and torsion tests in a universal testing machine, using relative stiffness as an evaluation parameter. Assemblies with intact humeri were analyzed for comparison. RESULTS: The biomechanical behavior of the fixation techniques varied within a wide range, where the assemblies including the DCP plate and the 4.5mm diameter screws

  1. Minicomputer For Biomechanical Research

    Science.gov (United States)

    Shierman, Gail; Rhymes, Tom

    1982-02-01

    The increased capabilities of minicomputers today allows a biomechanics laboratory to establish a self-contained computer system for a reasonable price. The system includes a microprocessor, a printer and a CRT. Analog to digital conversion is an important feature to consider as well as the ability to interface with a mainframe computer. A minicomputer adapted for film analysis should be a consideration for data analysis when developing a cinematography laboratory. For the past 10-15 years the area of biomechanics has enjoyed the advances in technology. Equipment and instrumentation once used exclusively by engineers and physicists have become readily available to those involved with snorts analyses. Among the various pieces of equipment accessible to biomechanists today, probably the most important one is the computer. At this time several biomechanics laboratories are using the computer to analyze kinematic and kinetic data obtained from film. The computer in use at each school is generally the main University or College computer with a remote terminal set-up in the biomechanics laboratory. This system functions well if there is adequate response from the time-sharing system of the main computer, and if there is at least one knowledgeable technician available. With the trend toward minicomputers today, their increased capabilities, and their ease of use, a self-contained minicomputer system in the biomechanics laboratory appears to be a viable alternative. The computer system in use in the ,Biomechanics Laboratory at the University of Oklahoma is based around the Cromemco Z2D computer connected to a PCD motion analyzer (Figure 1). The data acquisition system consists of the eight-bit microprocessor-based minicomputer connected to an analog to digital converter (ADC). As a terminal for the computer, we have either a video display unit or a Model 43 Teletype. The Model 43 provides a hard copy out-put while the video terminal provides much faster I/O, useful for

  2. Ulnar nerve dysfunction

    Science.gov (United States)

    Neuropathy - ulnar nerve; Ulnar nerve palsy; Mononeuropathy; Cubital tunnel syndrome ... neuropathy occurs when there is damage to the ulnar nerve. This ... syndrome may result. When damage destroys the nerve covering ( ...

  3. Cutaneous nerve entrapment syndrome

    Institute of Scientific and Technical Information of China (English)

    DongFuhui

    2004-01-01

    The cutaneous nerve entrapment syndrome is named that, the cutaneous nerve's functional disorder caused by some chronic entrapment, moreover appears a series of nerve's feeling obstacle,vegetative nerve function obstacle, nutrition obstacle, even motor function obstacle in various degree.

  4. Nerve biopsy (image)

    Science.gov (United States)

    Nerve biopsy is the removal of a small piece of nerve for examination. Through a small incision, a sample ... is removed and examined under a microscope. Nerve biopsy may be performed to identify nerve degeneration, identify ...

  5. Vagus Nerve Stimulation

    Science.gov (United States)

    Vagus nerve stimulation Overview By Mayo Clinic Staff Vagus nerve stimulation is a procedure that involves implantation of a device that stimulates the vagus nerve with electrical impulses. There's one vagus nerve on ...

  6. Microsurgical anatomy of the ocular motor nerves.

    Science.gov (United States)

    Zhang, Yi; Liu, Hao; Liu, En-Zhong; Lin, You-Zhi; Zhao, Shi-Guang; Jing, Guo-Hua

    2010-08-01

    This study was designed to provide anatomic data to help surgeons avoid damage to the ocular motor nerves during intraorbital operations. The microsurgical anatomy of the ocular motor nerves was studied in 50 adult cadaveric heads (100 orbits). Dissections were performed with a microscope. The nerves were exposed and the neural and muscular relationships of each portion of the nerve were examined and measured. The superior division of the oculomotor nerve coursed between the optic nerve and the superior rectus muscle after it left the annular tendon, and its branches entered into the superior rectus muscle and levator muscle. A mean of five fibers (range 3-7) innervated the superior rectus muscle, and a mean of one fiber (range 1-2) followed a medial direction (84%) or went straight through the superior rectus muscle (16%). The inferior division of the oculomotor nerve branched into the medial rectus, inferior rectus and inferior oblique muscles. The trochlear nerve ended on the orbital side of the posterior one-third of the superior oblique muscle in 76 specimens. The abducens nerve ended on the posterior one-third of the lateral rectus muscle in 86 specimens. If the belly of the lateral rectus muscle was divided into three superior-inferior parts, the nerve commonly entered into the middle one-third in 74 specimens. Based on the observed data, microanatomical relationships of the orbital contents were revised.

  7. Tumors Presenting as Multiple Cranial Nerve Palsies

    Directory of Open Access Journals (Sweden)

    Kishore Kumar

    2017-04-01

    Full Text Available Cranial nerve palsy could be one of the presenting features of underlying benign or malignant tumors of the head and neck. The tumor can involve the cranial nerves by local compression, direct infiltration or by paraneoplastic process. Cranial nerve involvement depends on the anatomical course of the cranial nerve and the site of the tumor. Patients may present with single or multiple cranial nerve palsies. Multiple cranial nerve involvement could be sequential or discrete, unilateral or bilateral, painless or painful. The presentation could be acute, subacute or recurrent. Anatomic localization is the first step in the evaluation of these patients. The lesion could be in the brain stem, meninges, base of skull, extracranial or systemic disease itself. We present 3 cases of underlying neoplasms presenting as cranial nerve palsies: a case of glomus tumor presenting as cochlear, glossopharyngeal, vagus and hypoglossal nerve palsies, clivus tumor presenting as abducens nerve palsy, and diffuse large B-cell lymphoma presenting as oculomotor, trochlear, trigeminal and abducens nerve palsies due to paraneoplastic involvement. History and physical examination, imaging, autoantibodies and biopsy if feasible are useful for the diagnosis. Management outcomes depend on the treatment of the underlying tumor.

  8. Lateralization Technique and Inferior Alveolar Nerve Transposition

    Directory of Open Access Journals (Sweden)

    Angélica Castro Pimentel

    2016-01-01

    Full Text Available Bone resorption of the posterior mandible can result in diminished bone edge and, therefore, the installation of implants in these regions becomes a challenge, especially in the presence of the mandibular canal and its contents, the inferior alveolar nerve. Several treatment alternatives are suggested: the use of short implants, guided bone regeneration, appositional bone grafting, distraction osteogenesis, inclined implants tangential to the mandibular canal, and the lateralization of the inferior alveolar nerve. The aim was to elucidate the success rate of implants in the lateralization technique and in inferior alveolar nerve transposition and to determine the most effective sensory test. We conclude that the success rate is linked to the possibility of installing implants with long bicortical anchor which favors primary stability and biomechanics.

  9. Lateralization Technique and Inferior Alveolar Nerve Transposition

    Science.gov (United States)

    Sanches, Marco Antonio; Ramalho, Gabriel Cardoso; Manzi, Marcello Roberto

    2016-01-01

    Bone resorption of the posterior mandible can result in diminished bone edge and, therefore, the installation of implants in these regions becomes a challenge, especially in the presence of the mandibular canal and its contents, the inferior alveolar nerve. Several treatment alternatives are suggested: the use of short implants, guided bone regeneration, appositional bone grafting, distraction osteogenesis, inclined implants tangential to the mandibular canal, and the lateralization of the inferior alveolar nerve. The aim was to elucidate the success rate of implants in the lateralization technique and in inferior alveolar nerve transposition and to determine the most effective sensory test. We conclude that the success rate is linked to the possibility of installing implants with long bicortical anchor which favors primary stability and biomechanics. PMID:27433360

  10. Biomechanical conditions of walking

    CERN Document Server

    Fan, Y F; Luo, L P; Li, Z Y; Han, S Y; Lv, C S; Zhang, B

    2015-01-01

    The development of rehabilitation training program for lower limb injury does not usually include gait pattern design. This paper introduced a gait pattern design by using equations (conditions of walking). Following the requirements of reducing force to the injured side to avoid further injury, we developed a lower limb gait pattern to shorten the stride length so as to reduce walking speed, to delay the stance phase of the uninjured side and to reduce step length of the uninjured side. This gait pattern was then verified by the practice of a rehabilitation training of an Achilles tendon rupture patient, whose two-year rehabilitation training (with 24 tests) has proven that this pattern worked as intended. This indicates that rehabilitation training program for lower limb injury can rest on biomechanical conditions of walking based on experimental evidence.

  11. Aeronautical Inspirations in Biomechanics

    Directory of Open Access Journals (Sweden)

    Maroński Ryszard

    2017-03-01

    Full Text Available Introduction. The goal of the paper is to show that some problems formulated in the dynamics of atmospheric flight are very similar to the problems formulated in the biomechanics of motion and medicine. Three problems were compared: minimumheat transfer from the boundary layer to the ballistic missile skin, minimum-time ski descent, and the minimisation of the negative cumulated effect of the drug in cancer chemotherapy. Material and methods. All these problems are solved using the same method originally developed for aerospace systems - the method of Miele (the extremisation method of linear integrals via Green’s theorem. Results. It is shown that the problems arising in different branches of knowledge are very similar in problem formulations, mathematical models, and solution methods used. Conclusions. There are no barriers between different disciplines.

  12. Head kinematics during shaking associated with abusive head trauma.

    Science.gov (United States)

    Lintern, T O; Puhulwelle Gamage, N T; Bloomfield, F H; Kelly, P; Finch, M C; Taberner, A J; Nash, M P; Nielsen, P M F

    2015-09-18

    Abusive head trauma (AHT) is a potentially fatal result of child abuse but the mechanisms of injury are controversial. To address the hypothesis that shaking alone is sufficient to elicit the injuries observed, effective computational and experimental models are necessary. This paper investigates the use of a coupled rigid-body computational modelling framework to reproduce in vivo shaking kinematics in AHT. A sagittal plane OpenSim computational model of a lamb was developed and used to interpret biomechanical data from in vivo shaking experiments. The acceleration of the head during shaking was used to provide in vivo validation of the associated computational model. Results of this study demonstrated that peak accelerations occurred when the head impacted the torso and produced acceleration magnitudes exceeding 200ms(-)(2). The computational model demonstrated good agreement with the experimental measurements and was shown to be able to reproduce the high accelerations that occur during impact. The biomechanical results obtained with the computational model demonstrate the utility of using a coupled rigid-body modelling framework to describe infant head kinematics in AHT.

  13. Systems biomechanics of the cell

    CERN Document Server

    Maly, Ivan V

    2013-01-01

    Systems Biomechanics of the Cell attempts to outline systems biomechanics of the cell as an emergent and promising discipline. The new field owes conceptually to cell mechanics, organism-level systems biomechanics, and biology of biochemical systems. Its distinct methodology is to elucidate the structure and behavior of the cell by analyzing the unintuitive collective effects of elementary physical forces that interact within the heritable cellular framework. The problematics amenable to this approach includes the variety of cellular activities that involve the form and movement of the cell body and boundary (nucleus, centrosome, microtubules, cortex, and membrane). Among the elementary system effects in the biomechanics of the cell, instability of symmetry, emergent irreversibility, and multiperiodic dissipative motion can be noted. Research results from recent journal articles are placed in this unifying framework. It is suggested that the emergent discipline has the potential to expand the spectrum of ques...

  14. Time-Dependent Lagrangian Biomechanics

    CERN Document Server

    Ivancevic, Tijana T

    2009-01-01

    In this paper we present the time-dependent generalization of an 'ordinary' autonomous human musculo-skeletal biomechanics. We start with the configuration manifold of human body, given as a set of its all active degrees of freedom (DOF). This is a Riemannian manifold with a material metric tensor given by the total mass-inertia matrix of the human body segments. This is the base manifold for standard autonomous biomechanics. To make its time-dependent generalization, we need to extend it with a real time axis. On this extended configuration space we develop time-dependent biomechanical Lagrangian dynamics, using derived jet spaces of velocities and accelerations, as well as the underlying geometric evolution of the mass-inertia matrix. Keywords: Human time-dependent biomechanics, configuration manifold, jet spaces, geometric evolution

  15. Neuralgias of the Trigeminal Nerve

    OpenAIRE

    Gordon, Allan S

    2000-01-01

    Practitioners are often presented with patients who complain bitterly of facial pain. The trigeminal nerve is involved in four conditions that are sometimes mixed up. The four conditions - trigeminal neuralgia, trigeminal neuropathic pain, postherpetic neuralgia and atypical facial pain - are discussed under the headings of clinical features, differential diagnosis, cause and treatment. This article should help practitioners to differentiate one from the other and to manage their care.

  16. Neuralgias of the Trigeminal Nerve

    Directory of Open Access Journals (Sweden)

    Allan S Gordon

    2000-01-01

    Full Text Available Practitioners are often presented with patients who complain bitterly of facial pain. The trigeminal nerve is involved in four conditions that are sometimes mixed up. The four conditions - trigeminal neuralgia, trigeminal neuropathic pain, postherpetic neuralgia and atypical facial pain - are discussed under the headings of clinical features, differential diagnosis, cause and treatment. This article should help practitioners to differentiate one from the other and to manage their care.

  17. Whole-globe biomechanics using high-field MRI.

    Science.gov (United States)

    Voorhees, Andrew P; Ho, Leon C; Jan, Ning-Jiun; Tran, Huong; van der Merwe, Yolandi; Chan, Kevin; Sigal, Ian A

    2017-07-01

    The eye is a complex structure composed of several interconnected tissues acting together, across the whole globe, to resist deformation due to intraocular pressure (IOP). However, most work in the ocular biomechanics field only examines the response to IOP over smaller regions of the eye. We used high-field MRI to measure IOP induced ocular displacements and deformations over the whole globe. Seven sheep eyes were obtained from a local abattoir and imaged within 48 h using MRI at multiple levels of IOP. IOP was controlled with a gravity perfusion system and a cannula inserted into the anterior chamber. T2-weighted imaging was performed to the eyes serially at 0 mmHg, 10 mmHg, 20 mmHg and 40 mmHg of IOP using a 9.4 T MRI scanner. Manual morphometry was conducted using 3D visualization software to quantify IOP-induced effects at the globe scale (e.g. axial length and equatorial diameters) or optic nerve head scale (e.g. canal diameter, peripapillary sclera bowing). Measurement sensitivity analysis was conducted to determine measurement precision. High-field MRI revealed an outward bowing of the posterior sclera and anterior bulging of the cornea due to IOP elevation. Increments in IOP from 10 to 40 mmHg caused measurable increases in axial length in 6 of 7 eyes of 7.9 ± 5.7% (mean ± SD). Changes in equatorial diameter were minimal, 0.4 ± 1.2% between 10 and 40 mmHg, and in all cases less than the measurement sensitivity. The effects were nonlinear, with larger deformations at normal IOPs (10-20 mmHg) than at elevated IOPs (20-40 mmHg). IOP also caused measurable increases in the nasal-temporal scleral canal diameter of 13.4 ± 9.7% between 0 and 20 mmHg, but not in the superior-inferior diameter. This study demonstrates that high-field MRI can be used to visualize and measure simultaneously the effects of IOP over the whole globe, including the effects on axial length and equatorial diameter, posterior sclera displacement and bowing, and even

  18. Selective activation of the human tibial and common peroneal nerves with a flat interface nerve electrode

    Science.gov (United States)

    Schiefer, M. A.; Freeberg, M.; Pinault, G. J. C.; Anderson, J.; Hoyen, H.; Tyler, D. J.; Triolo, R. J.

    2013-10-01

    Objective. Electrical stimulation has been shown effective in restoring basic lower extremity motor function in individuals with paralysis. We tested the hypothesis that a flat interface nerve electrode (FINE) placed around the human tibial or common peroneal nerve above the knee can selectively activate each of the most important muscles these nerves innervate for use in a neuroprosthesis to control ankle motion. Approach. During intraoperative trials involving three subjects, an eight-contact FINE was placed around the tibial and/or common peroneal nerve, proximal to the popliteal fossa. The FINE's ability to selectively recruit muscles innervated by these nerves was assessed. Data were used to estimate the potential to restore active plantarflexion or dorsiflexion while balancing inversion and eversion using a biomechanical simulation. Main results. With minimal spillover to non-targets, at least three of the four targets in the tibial nerve, including two of the three muscles constituting the triceps surae, were independently and selectively recruited in all subjects. As acceptable levels of spillover increased, recruitment of the target muscles increased. Selective activation of muscles innervated by the peroneal nerve was more challenging. Significance. Estimated joint moments suggest that plantarflexion sufficient for propulsion during stance phase of gait and dorsiflexion sufficient to prevent foot drop during swing can be achieved, accompanied by a small but tolerable inversion or eversion moment.

  19. A method to investigate the biomechanical alterations in Perthes’ disease by hip joint contact modeling

    DEFF Research Database (Denmark)

    Salmingo, Remel A.; Skytte, Tina Lercke; Traberg, Marie Sand

    2017-01-01

    . The healthy bone in the femoral head of the Perthes’ hip carries additional loads as indicated by the increase of stress levels around the necrotic-healthy bone interface. Identifying the biomechanical changes, such as the location of stress and contact pressure concentrations, is a prerequisite......Perthes’ disease is a destructive hip joint disorder characterized by malformation of the femoral head in young children. While the morphological changes have been widely studied, the biomechanical effects of these changes still need to be further elucidated. The objective of this study...... was to develop a method to investigate the biomechanical alterations in Perthes’ disease by finite element (FE ) contact modeling using MRI. The MRI data of a unilateral Perthes’ case was obtained to develop the three-dimensional FE model of the hip joint. The stress and contact pressure patterns...

  20. Biomechanics of whiplash injury

    Institute of Scientific and Technical Information of China (English)

    CHEN Hai-bin; King H YANG; WANG Zheng-guo

    2009-01-01

    Despite a large number of rear-end collisions on the road and a high frequency of whiplash injuries reported, the mechanism of whiplash injuries is not completely understood. One of the reasons is that the injury is not necessarily accompanied by obvious tissue damage detectable by X-ray or MRI. An extensive series of biomechanics studies, including injury epidemiology, neck kinematics,facet capsule ligament mechanics, injury mechanisms and injury criteria, were undertaken to help elucidate these whiplash injury mechanisms and gain a better understanding of cervical facet pain. These studies provide the following evidences to help explain the mechanisms of the whiplash injury: (1) Whiplash injuries are generally considered to be a soft tissue injury of the neck with symptoms such as neck pain and stiffness, shoulder weakness, dizziness, headache and memory loss, etc. (2) Based on kinematical studies on the cadaver and volunteers, there are three distinct periods that have the potential to cause injury to the neck. In the first stage, flexural deformation of the neck is observed along with a loss of cervical lordosis; in the second stage, the cervical spine assumes an S-shaped curve as the lower vertebrae begin to extend and gradually cause the upper vertebrae to extend; during the final stage, the entire neck is extended due to the extension moments at both ends. (3)The in vivo environment afforded by rodent models of injury offers particular utility for linking mechanics, nociception and behavioral outcomes. Experimental findings have examined strains across the facet joint as a mechanism of whiplash injury, and suggested a capsular strain threshold or a vertebral distraction threshold for whiplash-related injury,potentially producing neck pain. (4) Injuries to the facet capsule region of the neck are a major source of post-crash pain. There are several hypotheses on how whiplash-associated injury may occur and three of these injuries are related to strains within

  1. Biomechanics of whiplash injury.

    Science.gov (United States)

    Chen, Hai-bin; Yang, King H; Wang, Zheng-guo

    2009-10-01

    Despite a large number of rear-end collisions on the road and a high frequency of whiplash injuries reported, the mechanism of whiplash injuries is not completely understood. One of the reasons is that the injury is not necessarily accompanied by obvious tissue damage detectable by X-ray or MRI. An extensive series of biomechanics studies, including injury epidemiology, neck kinematics, facet capsule ligament mechanics, injury mechanisms and injury criteria, were undertaken to help elucidate these whiplash injury mechanisms and gain a better understanding of cervical facet pain. These studies provide the following evidences to help explain the mechanisms of the whiplash injury: (1) Whiplash injuries are generally considered to be a soft tissue injury of the neck with symptoms such as neck pain and stiffness, shoulder weakness, dizziness, headache and memory loss, etc. (2) Based on kinematical studies on the cadaver and volunteers, there are three distinct periods that have the potential to cause injury to the neck. In the first stage, flexural deformation of the neck is observed along with a loss of cervical lordosis; in the second stage, the cervical spine assumes an S-shaped curve as the lower vertebrae begin to extend and gradually cause the upper vertebrae to extend; during the final stage, the entire neck is extended due to the extension moments at both ends. (3) The in vivo environment afforded by rodent models of injury offers particular utility for linking mechanics, nociception and behavioral outcomes. Experimental findings have examined strains across the facet joint as a mechanism of whiplash injury, and suggested a capsular strain threshold or a vertebral distraction threshold for whiplash-related injury, potentially producing neck pain. (4) Injuries to the facet capsule region of the neck are a major source of post-crash pain. There are several hypotheses on how whiplash-associated injury may occur and three of these injuries are related to strains

  2. Judo Biomechanical Optimization

    CERN Document Server

    Sacripanti, Attilio

    2016-01-01

    In this paper, for the first time, there is comprehensively tackling the problem of biomechanical optimization of a sport of situation such as judo. Starting from the optimization of more simple sports, optimization of this kind of complex sports is grounded on a general physics tool such as the analysis of variation. The objective function is divided for static and dynamic situation of Athletes couple, and it is proposed also a sort of dynamic programming problem Strategic Optimization. A dynamic programming problem is an optimization problem in which decisions have to be taken sequentially over several time periods linked in some fashion. A strategy for a dynamic programming problem is just a contingency plan, a plan that specifies what is to be done at each stage as a function of all that has transpired up to that point. It is possible to demonstrate, under some conditions, that a Markovian optimal strategy is an optimal strategy for the dynamic programming problem under examination. At last we try to appr...

  3. Stability of the unlinked Latitude total elbow prosthesis: A biomechanical in vitro analysis

    NARCIS (Netherlands)

    Wagener, Marc L.; Vos, de Maarten J.; Hendriks, Jan C.M.; Eygendaal, Denise; Verdonschot, Nico

    2013-01-01

    Background The purpose of this study is to assess the valgus and varus laxity of the unlinked version of the Latitude total elbow prosthesis and the effects of radial head preservation or replacement. Methods Biomechanical analysis of the valgus and varus laxity of the unlinked Latitude was perform

  4. Stability of the unlinked Latitude total elbow prosthesis: A biomechanical in vitro analysis.

    NARCIS (Netherlands)

    Wagener, M.L.; Vos, M.J. de; Hendriks, J.C.M.; Eygendaal, D.; Verdonschot, N.J.J.

    2013-01-01

    BACKGROUND: The purpose of this study is to assess the valgus and varus laxity of the unlinked version of the Latitude total elbow prosthesis and the effects of radial head preservation or replacement. METHODS: Biomechanical analysis of the valgus and varus laxity of the unlinked Latitude was perfor

  5. New partnership between Virginia Tech Transportation Institute and Center for Injury Biomechanics receives first research grant

    OpenAIRE

    Box, Sherri

    2009-01-01

    A team of three Virginia Tech faculty members -- Stefan Duma, Warren Hardy, and H. Clay Gabler -- was recently awarded $2.6 million from U.S. Army Research Acquisition Activity to study the biomechanics of head, neck, and chest injury prevention for soldiers.

  6. A biomechanical model for the analysis of the cervical spine in static postures

    NARCIS (Netherlands)

    C.J. Snijders (Chris); G.A. Hoek van Dijke; E.R. Roosch (E.)

    1991-01-01

    textabstractTo gain a better understanding of the forces working on the cervical spine, a spatial biomechanical computer model was developed. The first part of our research was concerned with the development of a kinematic model to establish the axes of rotation and the mutual position of the head

  7. Study on Brain Injury Biomechanics Based on the Real Pedestrian Traffic Accidents

    Science.gov (United States)

    Feng, Chengjian; Yin, Zhiyong

    This paper aimed to research the dynamic response and injury mechanisms of head based on real pedestrian traffic accidents with video. The kinematics of head contact with the vehicle was reconstructed by using multi-body dynamics models. These calculated parameters such as head impact velocity and impact location and head orientation were applied to the THUMS-4 FE head model as initial conditions. The intracranial pressure and stress of brain were calculated from simulations of head contact with the vehicle. These results were consistent with that of others. It was proved that real traffic accidents combined with simulation analysis can be used to study head injury biomechanics. Increasing in the number of cases, a tolerance limit of brain injury will be put forward.

  8. The biomechanics of seed germination.

    Science.gov (United States)

    Steinbrecher, Tina; Leubner-Metzger, Gerhard

    2016-12-07

    From a biomechanical perspective, the completion of seed (and fruit) germination depends on the balance of two opposing forces: the growth potential of the embryonic axis (radicle-hypocotyl growth zone) and the restraint of the seed-covering layers (endosperm, testa, and pericarp). The diverse seed tissues are composite materials which differ in their dynamic properties based on their distinct cell wall composition and water uptake capacities. The biomechanics of embryo cell growth during seed germination depend on irreversible cell wall loosening followed by water uptake due to the decreasing turgor, and this leads to embryo elongation and eventually radicle emergence. Endosperm weakening as a prerequisite for radicle emergence is a widespread phenomenon among angiosperms. Research into the biochemistry and biomechanics of endosperm weakening has demonstrated that the reduction in puncture force of a seed's micropylar endosperm is environmentally and hormonally regulated and involves tissue-specific expression of cell wall remodelling proteins such as expansins, diverse hydrolases, and the production of directly acting apoplastic reactive oxygen. The endosperm-weakening biomechanics and its underlying cell wall biochemistry differ between the micropylar (ME) and chalazal (CE) endosperm domains. In the ME, they involve cell wall loosening, cell separation, and programmed cell death to provide decreased and localized ME tissue resistance, autolysis, and finally the formation of an ME hole required for radicle emergence. Future work will further unravel the molecular mechanisms, environmental regulation, and evolution of the diverse biomechanical cell wall changes underpinning the control of germination by endosperm weakening.

  9. Kinesiology/Biomechanics: Perspectives and Trends.

    Science.gov (United States)

    Atwater, Anne E.

    1980-01-01

    Past and recent developments and future directions in kinesiology and biomechanics are reviewed. Similarities and differences between these two areas are clarified. The areas of kinesiology and biomechanics have distinct unique qualities and should be treated as separate disciplines. (CJ)

  10. Facial nerve function in carcinoma of the parotid gland

    NARCIS (Netherlands)

    Terhaard, Chris; Lubsen, Herman; Tan, Bing; Merkx, Thijs; van der Laan, Bernard; Jong, Rob Baatenburg-de; Manni, Hans; Kneght, Paul

    2006-01-01

    Aim: To analyse, for patients with carcinoma of the parotid gland, the prognostic value for treatment outcome of the function of the facial nerve (NVII), and determining facial nerve dysfunction after treatment. Methods and materials: In a retrospective study of the Dutch head and Neck cooperative g

  11. Biomechanics and the wheelchair.

    Science.gov (United States)

    McLaurin, C A; Brubaker, C E

    1991-04-01

    Wheelchair biomechanics involves the study of how a wheelchair user imparts power to the wheels to achieve mobility. Because a wheelchair can coast, power input need not be continuous, but each power strike can be followed by a period of recovery, with the stroking frequency depending on user preferences and the coasting characteristics of the wheelchair. The latter is described in terms of rolling resistance, wind resistance and the slope of the surface. From these three factors the power required to propel the wheelchair is determined, and must be matched by the power output of the user. The efficiency of propulsion is the ratio of this power output to the metabolic cost and is typically in the order of 5% in normal use. The features required in a wheelchair depend upon user characteristics and intended activities. The ideal wheelchair for an individual will have the features that closely match these characteristics and activities. Thus prescription is not just choosing a wheelchair, but choosing the components of the wheelchair that best serve the intended purpose. In this paper, each component is examined for available options and how these options effect the performance of the wheelchair for the individual. The components include wheels, tyres, castors, frames, bearings, materials, construction details, seats, backrests, armrests, foot and legrests, headrests, wheel locks, running brakes, handrims, levers, accessories, adjustments and detachable parts. Each component is considered in relation to performance characteristics including rolling resistance, versatility, weight, comfort, stability, maneouvrability, transfer, stowage, durability and maintenance. Where they exist, wheelchair standards are referred to as a source of information regarding these characteristics.

  12. Time-Dependent Lagrangian Biomechanics

    OpenAIRE

    Ivancevic, Tijana T.

    2009-01-01

    In this paper we present the time-dependent generalization of an 'ordinary' autonomous human musculo-skeletal biomechanics. We start with the configuration manifold of human body, given as a set of its all active degrees of freedom (DOF). This is a Riemannian manifold with a material metric tensor given by the total mass-inertia matrix of the human body segments. This is the base manifold for standard autonomous biomechanics. To make its time-dependent generalization, we need to extend it wit...

  13. Biomechanical analysis of rollator walking

    DEFF Research Database (Denmark)

    Alkjaer, T; Larsen, Peter K; Pedersen, Gitte

    2006-01-01

    The rollator is a very popular walking aid. However, knowledge about how a rollator affects the walking patterns is limited. Thus, the purpose of the study was to investigate the biomechanical effects of walking with and without a rollator on the walking pattern in healthy subjects.......The rollator is a very popular walking aid. However, knowledge about how a rollator affects the walking patterns is limited. Thus, the purpose of the study was to investigate the biomechanical effects of walking with and without a rollator on the walking pattern in healthy subjects....

  14. Frontiers in Head and Neck Trauma: Clinical and Biomechanical.

    Science.gov (United States)

    2007-11-02

    the frontal, parietal and occipital bones that form the bulk of the convexity on top . The lateral aspect of the sphenoid bone meets the temporal bone...Bones The facial bones consist of fourteen bones: two nasal, two superior maxillary , two lachrymal, two malar, two palate, two inferior turbinate...vomer and inferior maxillary bones. These bones form the housing for most of the sensory structures of the human, including sight, smell and taste

  15. Bilateral high radial nerve compressions: a case report.

    Science.gov (United States)

    Chuangsuwanich, A; Muangsombut, S; Sangruchi, T

    2000-06-01

    A 40-year-old woman with bilateral high radial nerve compressions by non-traumatic cause was reported. It occurred first at the right radial nerve which was explored after a period of investigation and conservative treatment. Two constricted sites 2.0 cm apart of the right radial nerve crossed by branches of the radial collateral artery beneath the lateral head of the triceps were found. The constricted sites including tissue in between was resected and replaced with a sural nerve graft. One year later the patient had the same episode on the left side. The operative finding was the same as the previous one. Sural nerve graft was performed after neurolysis had failed. The patient's normal radial nerve function returned in one year. This is the first reported case in the literature of bilateral high radial nerve compressions by branches of the radial collateral artery.

  16. Clinical applications of biomechanics cinematography.

    Science.gov (United States)

    Woodle, A S

    1986-10-01

    Biomechanics cinematography is the analysis of movement of living organisms through the use of cameras, image projection systems, electronic digitizers, and computers. This article is a comparison of cinematographic systems and details practical uses of the modality in research and education.

  17. Is Heading in Youth Soccer Dangerous Play?

    Science.gov (United States)

    O'Kane, John W

    2016-01-01

    Soccer is among the most popular youth sports with over 3 million youth players registered in the U.S. Soccer is unique in that players intentionally use their head to strike the ball, leading to concerns that heading could cause acute or chronic brain injury, especially in the immature brains of children. Pub Med search without date restriction was conducted in November 2014 and August 2015 using the terms soccer and concussion, heading and concussion, and youth soccer and concussion. 310 articles were identified and reviewed for applicable content specifically relating to youth athletes, heading, and/or acute or chronic brain injury from soccer. Soccer is a low-risk sport for catastrophic head injury, but concussions are relatively common and heading often plays a role. At all levels of play, concussions are more likely to occur in the act of heading than with other facets of the game. While concussion from heading the ball without other contact to the head appears rare in adult players, some data suggests children are more susceptible to concussion from heading primarily in game situations. Contributing factors include biomechanical forces, less developed technique, and the immature brain's susceptibility to injury. There is no evidence that heading in youth soccer causes any permanent brain injury and there is limited evidence that heading in youth soccer can cause concussion. A reasonable approach based on U.S. Youth Soccer recommendations is to teach heading after age 10 in controlled settings, and heading in games should be delayed until skill acquisition and physical maturity allow the youth player to head correctly with confidence.

  18. Malignant peripheral nerve sheath tumor of the cervical vagus nerve in a neurofibromatosis type 1 patient - An unusual presentation

    Directory of Open Access Journals (Sweden)

    Ashok Gupta

    2010-07-01

    Full Text Available Malignant peripheral nerve sheath tumors (MPNST’S of the head and neck comprise 2% to 6% of head and neck sarcomas. These tumors may arise as sporadic variants or in patients with neurofibromatosis (NF. Development of these MPNST’s is one of the serious complications of neurofibromatosis type 1(NF1. To our knowledge there are only two reported cases of MPNST’s arising in the cervical vagal nerve, occurring in NF1 patients. We present here an NF1 patient who developed an MPNST of the cervical vagus nerve and presented only with a cervical swelling and hoarseness.

  19. ELECTRODIAGNOSTIC ASSESSMENT OF PERIPHERAL NERVE INJURIES IN KICK-BOXERS

    Directory of Open Access Journals (Sweden)

    M.R EMAD

    2002-06-01

    Full Text Available Introducti0n. Peripheral nerve injuries are one of the common traumas in various sport fields. Nowadays, thera are a growing tendency to Martial arts among young people. Insufficient knowlodage about the biomechanics and true skills in these sports can expose the athletes to many neuromusculoskeletal injuries including peripheral nerve injuries. The aim of this study was assessment of peripheral nerve injuries among Kick-boxers. Methods. The research was done on 30 male kick-boxers Aged between 17-28 years. Ulnar, tibial and median nerves were studied for the presence of unlar nerve entrapment on elbow, trasal tunnel syndrom and carpal tunnel syndrom. Results. Ulnar neuropathy was observed in 12 cases. Tibial entrapment was detected in 13 cases. No median nerve intrapment of CTS was detected. There was a significant correlation between the age of the participants and nerve entrapment. Discussion. Peripheral nerve injuries should be considered in athletes and should be trained to apply preventive and thrapeutic procedures.

  20. Optic Nerve Sheath Mechanics in VIIP Syndrome

    Science.gov (United States)

    Raykin, Julia; Forte, Taylor E.; Wang, Roy; Feola, Andrew; Samuels, Brian; Myers, Jerry; Nelson, Emily; Gleason, Rudy; Ethier, C. Ross

    2016-01-01

    Visual Impairment Intracranial Pressure (VIIP) syndrome is a major concern in current space medicine research. While the exact pathology of VIIP is not yet known, it is hypothesized that the microgravity-induced cephalad fluid shift increases intracranial pressure (ICP) and drives remodeling of the optic nerve sheath. To investigate this possibility, we are culturing optic nerve sheath dura mater samples under different pressures and investigating changes in tissue composition. To interpret results from this work, it is essential to first understand the biomechanical response of the optic nerve sheath dura mater to loading. Here, we investigated the effects of mechanical loading on the porcine optic nerve sheath.Porcine optic nerves (number: 6) were obtained immediately after death from a local abattoir. The optic nerve sheath (dura mater) was isolated from the optic nerve proper, leaving a hollow cylinder of connective tissue that was used for biomechanical characterization. We developed a custom mechanical testing system that allowed for unconfined lengthening, twisting, and circumferential distension of the dura mater during inflation and under fixed axial loading. To determine the effects of variations in ICP, the sample was inflated (0-60 millimeters Hg) and circumferential distension was simultaneously recorded. These tests were performed under variable axial loads (0.6 grams - 5.6 grams at increments of 1 gram) by attaching different weights to one end of the dura mater. Results and Conclusions: The samples demonstrated nonlinear behavior, similar to other soft connective tissue (Figure 1). Large increases in diameter were observed at lower transmural pressures (approximately 0 to 5 millimeters Hg), whereas only small diameter changes were observed at higher pressures. Particularly interesting was the existence of a cross-over point at a pressure of approximately 11 millimeters Hg. At this pressure, the same diameter is obtained for all axial loads applied

  1. Interventional effect of obturator nerve amputation on intraosseous high pressure in steroids-induced femoral head osteonecrosis%闭孔神经切断术对激素性股骨头缺血性坏死骨内高压的干预作用

    Institute of Scientific and Technical Information of China (English)

    曾文容; 唐毓金

    2013-01-01

    目的 探讨闭孔神经切断术对激素性股骨头坏死(SANFH)的骨内压、局部组织血液流变功能改变的影响.方法 选用健康成年家兔40只,随机分为对照组(9只)、模型组(15只)和治疗组(16只).对照组每周皮下注射生理盐水,模型组和治疗组均采用每周皮下注射醋酸泼尼松龙的方法成功制备兔早期激素性股骨头坏死的动物模型.4周后,治疗组行闭孔神经切断术,分别选取实验前、激素注射后4周(术前)、8周3个时间点,每组行骨内压测定并随机处死3只进行股骨头大体观察、HE染色、透射电镜下观察.结果 模型组和治疗组家兔实验后4、8周比对照组骨内压及股骨头空骨陷窝率增高(P<0.05);到8周时治疗组骨内压及股骨头空骨陷窝率下降,与模型组比较,差异有统计学意义(P<0.05).结论 闭孔神经切断术可以降低激素性股骨头坏死骨内压,可有效地延缓或降低股骨头坏死的发生.%Objective To investigate the effects of obturator nerve amputation on the intraosseous pressure and hemorrheological function change of local tissues in steroid-induced avascular necrosis of femoral head(SANFH). Methods 40 healthy adult Chinese white rabbits were selected and randomly divided into three groups:the control group(9 cases) ,the model group(15 cases) and the treatment group(16 cases). The control group was given saline by subcutaneous injection weekly. The other two groups were given prednisolone acetate by subcutaneous injection weekly for constructing the rabbit model of early steroid-induced femoral head necrosis. The obturator nerve was amputated after 4 weeks in the treatment group. A total of three time points were selected,including pre-experiment,4 weeks after steroid injection(preoperativc) and 8 weeks. The intraosseous pressure of femoral head was measured in each group and at three time points. Then,three rabbits were randomly selected and sacrificed for the femoral heads gross

  2. Nerve ring of the hypostome in hydra. I. Its structure, development, and maintenance

    DEFF Research Database (Denmark)

    Koizumi, O; Itazawa, M; Mizumoto, H

    1992-01-01

    neuronal complex consisting of a thick nerve bundle running circumferentially at the border between the hypostome and tentacle zone. Immunostaining showed that the nerve ring was heterogeneous and contained at least four different subsets of neurons. During head regeneration and budding, the nerve ring......The anatomy and developmental dynamics of the nerve ring in the hypostome of Hydra oligactis were examined immunocytochemically with an antiserum against a neuropeptide and with neuron-specific monoclonal antibodies. The nerve ring is unique in the mesh-like nerve net of hydra. It is a distinct...... appeared only after the nerve net of ganglion and sensory cells had formed. Every epithelial cell is continuously displaced with neurons toward either head or foot in an adult hydra. However, the ectoderm in the immediate vicinity of, and including, the nerve ring constitutes a stationary zone...

  3. Imaging of muscular denervation secondary to motor cranial nerve dysfunction

    Energy Technology Data Exchange (ETDEWEB)

    Connor, S.E.J. [Neuroradiology Department, Kings College Hospital, Denmark Hill, London SE5 9RS (United Kingdom)]. E-mail: sejconnor@tiscali.co.uk; Chaudhary, N. [Neuroradiology Department, Kings College Hospital, Denmark Hill, London SE5 9RS (United Kingdom); Fareedi, S. [Neuroradiology Department, Kings College Hospital, Denmark Hill, London SE5 9RS (United Kingdom); Woo, E.K. [Neuroradiology Department, Kings College Hospital, Denmark Hill, London SE5 9RS (United Kingdom)

    2006-08-15

    The effects of motor cranial nerve dysfunction on the computed tomography (CT) and magnetic resonance imaging (MRI) appearances of head and neck muscles are reviewed. Patterns of denervation changes are described and illustrated for V, VII, X, XI and XII cranial nerves. Recognition of the range of imaging manifestations, including the temporal changes in muscular appearances and associated muscular grafting or compensatory hypertrophy, will avoid misinterpretation as local disease. It will also prompt the radiologist to search for underlying cranial nerve pathology, which may be clinically occult. The relevant cranial nerve motor division anatomy will be described to enable a focussed search for such a structural abnormality.

  4. Surgical outcomes following nerve transfers in upper brachial plexus injuries

    Directory of Open Access Journals (Sweden)

    Bhandari P

    2009-01-01

    Full Text Available Background: Brachial plexus injuries represent devastating injuries with a poor prognosis. Neurolysis, nerve repair, nerve grafts, nerve transfer, functioning free-muscle transfer and pedicle muscle transfer are the main surgical procedures for treating these injuries. Among these, nerve transfer or neurotization is mainly indicated in root avulsion injury. Materials and Methods: We analysed the results of various neurotization techniques in 20 patients (age group 20-41 years, mean 25.7 years in terms of denervation time, recovery time and functional results. The inclusion criteria for the study included irreparable injuries to the upper roots of brachial plexus (C5, C6 and C7 roots in various combinations, surgery within 10 months of injury and a minimum follow-up period of 18 months. The average denervation period was 4.2 months. Shoulder functions were restored by transfer of spinal accessory nerve to suprascapular nerve (19 patients, and phrenic nerve to suprascapular nerve (1 patient. In 11 patients, axillary nerve was also neurotized using different donors - radial nerve branch to the long head triceps (7 patients, intercostal nerves (2 patients, and phrenic nerve with nerve graft (2 patients. Elbow flexion was restored by transfer of ulnar nerve motor fascicle to the motor branch of biceps (4 patients, both ulnar and median nerve motor fascicles to the biceps and brachialis motor nerves (10 patients, spinal accessory nerve to musculocutaneous nerve with an intervening sural nerve graft (1 patient, intercostal nerves (3rd, 4th and 5th to musculocutaneous nerve (4 patients and phrenic nerve to musculocutaneous nerve with an intervening graft (1 patient. Results: Motor and sensory recovery was assessed according to Medical Research Council (MRC Scoring system. In shoulder abduction, five patients scored M4 and three patients M3+. Fair results were obtained in remaining 12 patients. The achieved abduction averaged 95 degrees (range, 50 - 170

  5. Post-Traumatic Isolated Bilateral Sixth Nerve Palsy

    Directory of Open Access Journals (Sweden)

    Jain

    2016-03-01

    Full Text Available Introduction Here we discussed an unusual case of head injury with bilateral sixth nerve palsy without any other neurological deficit. A 40-year-old male was admitted with double vision after an episode of head injury. Case Presentation On examination bilateral lateral rectus palsy was present. No other positive finding recorded in general physical, neurological and ophthalmological examinations. Conclusions Bilaterality of the abducent nerve paralysis is uncommon. It is usually associated with major head injury with brain stem injury and associated neurological findings.

  6. Histological observation on acellular nerve grafts co-cultured with Schwann cells for repairing defects of the sciatic nerve

    Institute of Scientific and Technical Information of China (English)

    Xiaohong Sun; Jiangyi Tian; Xiaojie Tong; Xu Zhang; Zheng He

    2006-01-01

    myeline sheath were observed under electron microscope. ② The images were processed with the Mias-1000 imaging analytical system to calculate the number of myelinated nerve fibers, and the thickness of myeline sheath.RESULTS: All the 24 Wistar rats were involved in the analysis of results. ① Results observed under transmission electron microscope: The regenerated myelinated nerve fibers in the group of acellular nerve grafts with Schwann cells were more even than those in the group of acellular nerve grafts, the number of myelinated nerve fibers and thickness of myelin sheath were close to those in the allografts group (P > 0.05),but significantly different from those in the group of acellular nerve grafts (P < 0.05). ② Results observed under scanning electron microscope: A great amount of Schwann cells with two polars were observed in the group of grafts with Schwann cells, the feature of cultured Schwann cells showed shoulder by shoulder,head to head. ③ The number of myelinated nerve fibers and thickness of myelin sheath analyzed by Mias-1000 imaging system in the group of acellular nerve grafts with Schwann cells were close to those in the autografts group (P > 0.05), but significantly different from those in the group of acellular nerve grafts (P < 0.05).CONCLUSION: Host axonal regeneration is significantly increased after implant of acellular nerve grafts.Acellular nerve grafts with Schwann cells offers a novel approach for repairing the gap of nerve defect.

  7. Biomechanics of seat belt restraint system.

    Science.gov (United States)

    Sances, Anthony; Kumaresan, Srirangam; Herbst, Brian; Meyer, Steve; Hock, Davis

    2004-01-01

    Seat belt system restrains and protects occupants in motor vehicle crashes and any slack in seat belt system induces additional loading on occupant. Signs of belt loading are more obvious in high-speed frontal collisions with heavy occupants. However subtle changes may occur at low speeds or with low forces from occupants during rollovers. In certain cases, the seat belt webbing is twisted and loaded by the occupant. The loading of webbing induces an observable fold/crimp on the seat belt. The purpose of the study is to biomechanically evaluate the force required to produce such marks using an anthropometric physical test dummy. Two tests were conducted to determine the amount of force required to put an observable fold/crimp in a shoulder belt. A head form designed by Voight Hodgson was used to represent the neck which interacted with the belt. The force was applied with a pneumatic pull ram (central hydraulic 89182 N) and the force was measured with a 44,000 N transducer load cell (DSM-10K). Results indicate that the force of over 1,000 N produced a fold or crimp in the belt.

  8. INTRAOPERATIVE NEUROMONITORING DURING HEAD AND NECK SURGERY

    Directory of Open Access Journals (Sweden)

    P. O. Rumyantsev

    2012-01-01

    Full Text Available This clinical trial comparatively analyzed the frequency of postoperative neurological complications due to damage to motor (facial, recurrent, laryngeal, and accessory nerves after head and neck operations using the traditional procedure or intraoperative neuromonitoring. Neuromonitoring made during operations on the thyroid and level VI central neck could reduce the rate of recurrent laryngeal nerve paralysis by more than twice (OR = 0.32; 95 % CI 0.11–0.86; p = 0.028. The author considers the absolute indication for intraoperative neuromonitoring to be high-risk surgery for nondeliberate damage to the motor nerves and impossibility of their visual detection.

  9. The biomechanics of cervical spondylosis.

    Science.gov (United States)

    Ferrara, Lisa A

    2012-01-01

    Aging is the major risk factor that contributes to the onset of cervical spondylosis. Several acute and chronic symptoms can occur that start with neck pain and may progress into cervical radiculopathy. Eventually, the degenerative cascade causes desiccation of the intervertebral disc resulting in height loss along the ventral margin of the cervical spine. This causes ventral angulation and eventual loss of lordosis, with compression of the neural and vascular structures. The altered posture of the cervical spine will progress into kyphosis and continue if the load balance and lordosis is not restored. The content of this paper will address the physiological and biomechanical pathways leading to cervical spondylosis and the biomechanical principles related to the surgical correction and treatment of kyphotic progression.

  10. The Biomechanics of Cervical Spondylosis

    Directory of Open Access Journals (Sweden)

    Lisa A. Ferrara

    2012-01-01

    Full Text Available Aging is the major risk factor that contributes to the onset of cervical spondylosis. Several acute and chronic symptoms can occur that start with neck pain and may progress into cervical radiculopathy. Eventually, the degenerative cascade causes desiccation of the intervertebral disc resulting in height loss along the ventral margin of the cervical spine. This causes ventral angulation and eventual loss of lordosis, with compression of the neural and vascular structures. The altered posture of the cervical spine will progress into kyphosis and continue if the load balance and lordosis is not restored. The content of this paper will address the physiological and biomechanical pathways leading to cervical spondylosis and the biomechanical principles related to the surgical correction and treatment of kyphotic progression.

  11. Biomechanics of Gait during Pregnancy

    OpenAIRE

    2014-01-01

    Introduction. During pregnancy women experience several changes in the body’s physiology, morphology, and hormonal system. These changes may affect the balance and body stability and can cause discomfort and pain. The adaptations of the musculoskeletal system due to morphological changes during pregnancy are not fully understood. Few studies clarify the biomechanical changes of gait that occur during pregnancy and in postpartum period. Purposes. The purpose of this re...

  12. Confidence crisis of results in biomechanics research.

    Science.gov (United States)

    Knudson, Duane

    2017-11-01

    Many biomechanics studies have small sample sizes and incorrect statistical analyses, so reporting of inaccurate inferences and inflated magnitude of effects are common in the field. This review examines these issues in biomechanics research and summarises potential solutions from research in other fields to increase the confidence in the experimental effects reported in biomechanics. Authors, reviewers and editors of biomechanics research reports are encouraged to improve sample sizes and the resulting statistical power, improve reporting transparency, improve the rigour of statistical analyses used, and increase the acceptance of replication studies to improve the validity of inferences from data in biomechanics research. The application of sports biomechanics research results would also improve if a larger percentage of unbiased effects and their uncertainty were reported in the literature.

  13. Hominin Hip Biomechanics: Changing Perspectives.

    Science.gov (United States)

    Warrener, Anna G

    2017-05-01

    The shape of the human pelvis reflects the unique demands placed on the hip abductor muscles (gluteus medius and gluteus minimus), which stabilize the body in the frontal plane during bipedal locomotion. This morphological shift occurred early in hominin evolution, yet important shape differences between hominin species have led to significant disagreement about abductor function and locomotor capability in these extinct taxa. A static biomechanical model that relies on a close association between skeletal measurements of the pelvis and femur has traditionally been used to reconstruct hip biomechanics in these species. However, experimental biomechanical approaches have highlighted the dynamic nature of mediolateral balance in walking and running, challenging the assumptions of the static hip model. This article reviews traditional approaches for understanding hip abductor function, shows how they have been applied to the fossil hominin record, and discusses new techniques that integrate the dynamic nature of mediolateral balance during human locomotion. Anat Rec, 300:932-945, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  14. Musculocutaneous nerve substituting for the distal part of radial nerve: A case report and its embryological basis

    Directory of Open Access Journals (Sweden)

    A S Yogesh

    2011-01-01

    Full Text Available In the present case, we have reported a unilateral variation of the radial and musculocutaneous nerves on the left side in a 64-year-old male cadaver. The radial nerve supplied all the heads of the triceps brachii muscle and gave cutaneous branches such as lower lateral cutaneous nerve of the arm and posterior cutaneous nerve of forearm. The radial nerve ended without continuing further. The musculocutaneous nerve supplied the brachioradialis, extensor carpi radialis longus and extensor carpi radialis brevis muscles. The musculocutaneous nerve divided terminally into two branches, superficial and deep. The deep branch of musculocutaneous nerve corresponded to usual deep branch of the radial nerve while the superficial branch of musculocutaneous nerve corresponded to usual superficial branch of the radial nerve. The dissection was continued to expose the entire brachial plexus from its origin and it was found to be normal. The structures on the right upper limb were found to be normal. Surgeons should keep such variations in mind while performing the surgeries of the upper limb.

  15. Biomechanics of Pediatric Manual Wheelchair Mobility

    OpenAIRE

    2015-01-01

    Currently, there is limited research of the biomechanics of pediatric manual wheelchair mobility. Specifically, the biomechanics of functional tasks and their relationship to joint pain and health is not well understood. To contribute to this knowledge gap, a quantitative rehabilitation approach was applied for characterizing upper extremity biomechanics of manual wheelchair mobility in children and adolescents during propulsion, starting and stopping tasks. A Vicon motion analysis system ...

  16. Sport and Exercise Biomechanics (Bios Instant Notes)

    OpenAIRE

    Paul Grimshaw; Adrian Lees; Neil Fowler; Adrian Burden

    2007-01-01

    DESCRIPTION Instant Notes on Sport and Exercise Biomechanics provides a broad overview of the fundamental concepts in exercise and sport biomechanics. PURPOSE The book aims to provide instant notes on essential information about biomechanics, and is designed to help undergraduate students to grasp the corresponding subjects in physical effort rapidly and easily. AUDIENCE The book provides a useful resource for undergraduate and graduate students as a fundamental reference book. For the resear...

  17. Minimizing Head Acceleration in Soccer: A Review of the Literature.

    Science.gov (United States)

    Caccese, Jaclyn B; Kaminski, Thomas W

    2016-11-01

    Physicians and healthcare professionals are often asked for recommendations on how to keep athletes safe during contact sports such as soccer. With an increase in concussion awareness and concern about repetitive subconcussion, many parents and athletes are interested in mitigating head acceleration in soccer, so we conducted a literature review on factors that affect head acceleration in soccer. We searched electronic databases and reference lists to find studies using the keywords 'soccer' OR 'football' AND 'head acceleration'. Because of a lack of current research in soccer heading biomechanics, this review was limited to 18 original research studies. Low head-neck segment mass predisposes athletes to high head acceleration, but head-neck-torso alignment during heading and follow-through after contact can be used to decrease head acceleration. Additionally, improvements in symmetric neck flexor and extensor strength and neuromuscular neck stiffness can decrease head acceleration. Head-to-head impacts and unanticipated ball contacts result in the highest head acceleration. Ball contacts at high velocity may also be dangerous. The risk of concussive impacts may be lessened through the use of headgear, but headgear may also cause athletes to play more recklessly because they feel a sense of increased security. Young, but physically capable, athletes should be taught proper heading technique in a controlled setting, using a carefully planned progression of the skill.

  18. Developmental biomechanics of neck musculature

    OpenAIRE

    Lavallee, Amy V.; Ching, Randal P.; Nuckley, David J.

    2012-01-01

    Neck mechanics is central to head injury prevention since it is the musculoskeletal neck, which dictates the position and movement of the head. In the US, traumatic injury is the leading cause of death for children; however prevention is hampered by the lack of data concerning the mechanics of the immature head-and-neck. Thus, the objective of this study was to quantify neck muscle strength and endurance across the maturation spectrum and correlate these with head-and-neck anthropometry. A fa...

  19. Schwannomas of the head and neck

    Directory of Open Access Journals (Sweden)

    Anastasios Kanatas

    2011-12-01

    Full Text Available Schwannomas are benign encapsulated nerve sheath tumors composed of Schwann cells. Malignant change in head and neck schwannomas is rare, with the incidence varying between 8 and 13.9%. In this review, we discuss the presentation and the management of head and neck schwannomas. The issues and difficulties based on our own experience as well as the experience of published reports from the literature are presented.

  20. Numerical Reconstruction and Injury Biomechanism in a Car-Pedestrian Crash Accident

    Institute of Scientific and Technical Information of China (English)

    ZOU Dong-hua; LI Zheng-dong; SHAO Yu; FENG Hao; CHEN Jian-guo; LIU Ning-guo; HUANG Ping; CHEN Yi-jiu

    2012-01-01

    Objective To reconstruct a car-pedestrian crash accident using numerical simulation technology and explore the injury biomechanism as forensic evidence for injury identification.Methods An integration of multi-body dynamic,finite elcment (FE),and classical method was applied to a car-pedestrian crash accident.The location of the collision and the details of the traffic accident were determined by vehicle trace verification and autopsy.The accident reconstruction was performed by coupling the three-dimensional car behavior from PC-CRASH with a MADYMO dummy model.The collision FE models of head and leg,developed from CT scans of human remains,were loaded with calculated dummy collision parameters.The data of the impact biomechanical responses were extracted in terms of von Mises stress,relative displacement,strain and stress fringes.Results The accident reconstruction results were identical with the examined ones and the biomechanism of head and leg injuries,illustrated through the FE methods,were consistent with the classical injury theories.Conclusion The numerical simulation technology is proved to be effective in identifying traffic accidents and exploring of injury biomechanism.

  1. Biomechanics of the spine. Part I: Spinal stability

    Energy Technology Data Exchange (ETDEWEB)

    Izzo, Roberto, E-mail: roberto1766@interfree.it [Neuroradiology Department, “A. Cardarelli” Hospital, Napoli (Italy); Guarnieri, Gianluigi, E-mail: gianluigiguarnieri@hotmail.it [Neuroradiology Department, “A. Cardarelli” Hospital, Napoli (Italy); Guglielmi, Giuseppe, E-mail: g.gugliemi@unifg.it [Department of Radiology, University of Foggia, Foggia (Italy); Muto, Mario, E-mail: mutomar@tiscali.it [Neuroradiology Department, “A. Cardarelli” Hospital, Napoli (Italy)

    2013-01-15

    Biomechanics, the application of mechanical principles to living organisms, helps us to understand how all the bony and soft spinal components contribute individually and together to ensure spinal stability, and how traumas, tumours and degenerative disorders exert destabilizing effects. Spine stability is the basic requirement to protect nervous structures and prevent the early mechanical deterioration of spinal components. The literature reports a number of biomechanical and clinical definitions of spinal stability, but a consensus definition is lacking. Any vertebra in each spinal motion segment, the smallest functional unit of the spine, can perform various combinations of the main and coupled movements during which a number of bony and soft restraints maintain spine stability. Bones, disks and ligaments contribute by playing a structural role and by acting as transducers through their mechanoreceptors. Mechanoreceptors send proprioceptive impulses to the central nervous system which coordinates muscle tone, movement and reflexes. Damage to any spinal structure gives rise to some degree of instability. Instability is classically considered as a global increase in the movements associated with the occurrence of back and/or nerve root pain. The assessment of spinal instability remains a major challenge for diagnostic imaging experts. Knowledge of biomechanics is essential in view of the increasing involvement of radiologists and neuroradiologists in spinal interventional procedures and the ongoing development of new techniques and devices. Bioengineers and surgeons are currently focusing on mobile stabilization systems. These systems represent a new frontier in the treatment of painful degenerative spine and aim to neutralize noxious forces, restore the normal function of spinal segments and protect the adjacent segments. This review discusses the current concepts of spine stability.

  2. Biomechanics of sclera crosslinked using genipin in rabbit

    Directory of Open Access Journals (Sweden)

    Tai-Xiang Liu

    2017-03-01

    Full Text Available AIM: To strengthen the biomechanics of collagen by crosslinking rabbit scleral collagen with genipin to develop a new therapy for preventing myopic progression. METHODS: Ten New Zealand rabbits were treated with 0.5 mmol/L genipin injected into the sub-Tenon’s capsule in the right eyes. Untreated contralateral eyes served as the control. The treated area was cut into scleral strips measuring 4.0 mm×10.0 mm for stress-strain measurements (n=5. The remaining five treated eyes were prepared for histological examination. RESULTS: Compared to the untreated scleral strips, the genipin-crosslinked scleral strips showed that the ultimate stress and Young’s modulus at 10% strain were increased by the amplitude of 130% and 303% respectively, ultimate strain was decreased by 24%. There had no (-smooth muscle actin ((-SMA positive cells in control and treated sclera. Histologically, there was no sign of apoptosis in the sclera, choroid, and retina; and no side effects were found in the peripheral cornea and optic nerve adjacent to the treatment area. CONCLUSION: Genipin induced crosslinking of collagen can increase its biomechanical behavior by direct strengthening of the extracellular matrix in rabbit sclera, with no (-SMA expression seen in the myofibroblasts. As there is no evidence of cytotoxicity in the scleral, choroidal, and retinal cells, genipin is likely a promising agent to strengthen the weakened sclera to prevent myopic progression.

  3. [Spinal accessory nerve and lymphatic neck dissection].

    Science.gov (United States)

    Pinsolle, V; Michelet, V; Majoufre, C; Caix, P; Siberchicot, F; Pinsolle, J

    1997-09-01

    Radical neck dissection was the golden standard of treatment for cervical nodes in head and neck tumors. From the seventies, the preservation of the spinal accessory nerve has become increasingly popular in order to improve the functional result of the neck dissections. The aim of this study was to assess the degree of functional disability associated with each type of neck dissection and the value of anatomical references for dissection of the spinal accessory nerve. One hundred twenty seven patients were evaluated 1 month and 1 year after radical, functional or supraomohyoid neck dissection with a questionnaire and a physical examination. Anatomical measurements of the spinal accessory nerve were performed in 20 patients. We found considerable or severe shoulder dysfunction in 7%, 34% and 51% respectively of patients in whom supraomohyoid, functional and radical neck dissections were performed. Furthermore 49% of patients having undergone a radical neck dissection had little or no symptoms. Sacrifice of the spinal accessory nerve in radical neck dissection may lead to shoulder dysfunction. A functional disability may also be associated, although in a less extent, with any neck dissection in which the spinal accessory nerve is dissected and placed in traction. There is a large variation in the degree of functional disability and pain in patients with similar neck dissections. The course of the spinal accessory nerve in the neck makes it particularly vulnerable to injury during the dissection near the sternocleidomastoid muscle and in the posterior cervical triangle.

  4. A review of biomechanics of the shoulder and biomechanical concepts of rotator cuff repair

    Directory of Open Access Journals (Sweden)

    Nobuyuki Yamamoto

    2015-01-01

    Full Text Available In this article, we describe the basic knowledge about shoulder biomechanics, which is thought to be useful for surgeons. Some clinical reports have described that the excellent outcome after cuff repair without acromioplasty and a limited acromioplasty might be enough for subacromial decompression. It was biomechanically demonstrated that a 10-mm medial shift of the tendon repair site has a minimum effect on biomechanics. Many biomechanical studies reported that the transosseous equivalent repair was superior to other techniques, although the tendon may lose its inherent elasticity. We herein introduce our recent experiment data and latest information on biomechanics.

  5. Nerve conduction velocity

    Science.gov (United States)

    ... to measure the speed of the nerve signals. Electromyography (recording from needles placed into the muscles) is ... Often, the nerve conduction test is followed by electromyography (EMG). In this test, needles are placed into ...

  6. Common peroneal nerve dysfunction

    Science.gov (United States)

    ... toe-out movements Tests of nerve activity include: Electromyography (EMG, a test of electrical activity in muscles) Nerve ... Peroneal neuropathy. In: Preston DC, Shapiro BE, eds. Electromyography and Neuromuscular Disorders . 3rd ed. Philadelphia, PA: Elsevier; ...

  7. Head Injuries

    Science.gov (United States)

    ... object that's stuck in the wound. previous continue Concussions Concussions — the temporary loss of normal brain function due ... also a type of internal head injury. Repeated concussions can permanently damage the brain. In many cases, ...

  8. Head Tilt

    Science.gov (United States)

    ... Healthy Living Healthy Living Healthy Living Nutrition Fitness Sports Oral Health Emotional Wellness Growing Healthy Sleep Safety & ... When this happens, the neck muscles go into spasm, causing the head to tilt to one side. ...

  9. Head Injuries

    Science.gov (United States)

    ... ATV) Safety Balance Disorders Knowing Your Child's Medical History First Aid: Falls First Aid: Head Injuries Preventing Children's Sports Injuries Getting Help: Know the Numbers Concussions Stay Safe: Baseball Concussions Concussions: Getting Better Sports and Concussions Dealing ...

  10. Biomechanical evaluation of a unicortical button versus interference screw for subpectoral biceps tenodesis.

    Science.gov (United States)

    Arora, Amarpal S; Singh, Anshu; Koonce, Ryan C

    2013-04-01

    The purpose of this study was to evaluate and compare the biomechanical properties of a unicortical button with an interference screw used for subpectoral biceps tenodesis. We also describe the anatomic dangers of bicortical button use in the subpectoral location. Twenty-eight fresh-frozen human cadaveric shoulders with a mean age of 52 years were studied. The specimens were randomly divided into 4 experimental biceps tenodesis groups (n = 7): unicortical button, interference screw, bicortical suspensory button, and bicortical suspensory with interference screw (Arthrex, Naples, FL). Each tenodesis specimen was mounted on a mechanical testing machine, preloaded for 2 minutes at 5 N, cycled from 5 to 70 N for 500 cycles (1 Hz), and loaded to failure (1 mm/s). We determined the mode of failure and computed the ultimate load to failure, yield load, pullout stiffness, and displacement at peak load. Calculations of the distance between the axillary and radial nerves with respect to the bicortical buttons were also calculated in 6 specimens. There was no statistically significant difference (P > .05) among groups in terms of age, ultimate load to failure, pullout stiffness, or displacement at peak load. Suture-tendon interface failure was the most commonly observed mode of failure. The axillary nerve was on average 7.8 mm from the bicortical button; however, in 6 specimens the nerve was less than 3 mm away. The use of a unicortical button for subpectoral biceps tenodesis provides biomechanical properties similar to the use of an interference screw. In addition, the use of a bicortical button in this area of the proximal humerus puts the axillary nerve at risk. Using a unicortical button subpectoral biceps method may provide a surgeon with a safe and technically easy and reproducible technique while providing similar biomechanical properties to a known standard implant. Copyright © 2013 Arthroscopy Association of North America. Published by Elsevier Inc. All rights

  11. The Physics of Nerves

    CERN Document Server

    Heimburg, Thomas

    2010-01-01

    The accepted model for nerve pulse propagation in biological membranes seems insufficient. It is restricted to dissipative electrical phenomena and considers nerve pulses exclusively as a microscopic phenomenon. A simple thermodynamic model that is based on the macroscopic properties of membranes allows explaining more features of nerve pulse propagation including the phenomenon of anesthesia that has so far remained unexplained.

  12. Ganglioneuromas involving the hypoglossal nerve and the vagus nerve in a child: Surgical difficulties.

    Science.gov (United States)

    Bakshi, Jaimanti; Mohammed, Abdul Wadood; Lele, Saudamini; Nada, Ritambra

    2016-02-01

    Ganglioneuromas are benign tumors that arise from the Schwann cells of the autonomic nervous system. They are usually seen in the posterior mediastinum and the paraspinal retroperitoneum in relation to the sympathetic chain. In the head and neck, they are usually related to the cervical sympathetic ganglia or to the ganglion nodosum of the vagus nerve or the hypoglossal nerve. We describe what we believe is the first reported case of multiple ganglioneuromas of the parapharyngeal space in which two separate cranial nerves were involved. The patient was a 10-year-old girl who presented with a 2-year history of a painless and slowly progressive swelling on the left side of her neck and a 1-year history hoarseness. She had no history of relevant trauma or surgery. Intraoperatively, we found two tumors in the left parapharyngeal space-one that had arisen from the hypoglossal nerve and the other from the vagus nerve. Both ganglioneuromas were surgically removed, but the affected nerves had to be sacrificed. Postoperatively, the patient exhibited hypoglossal nerve and vocal fold palsy, but she was asymptomatic. In addition to the case description, we discuss the difficulties we faced during surgical excision.

  13. Exploring the biomechanics of taurodontism

    Science.gov (United States)

    Benazzi, Stefano; Nguyen, Huynh N; Kullmer, Ottmar; Hublin, Jean-Jacques

    2015-01-01

    Taurodontism (i.e. enlarged pulp chamber with concomitant apical displacement of the root bi/trifurcation) is considered a dental anomaly with relatively low incidence in contemporary societies, but it represents a typical trait frequently found in Neandertal teeth. Four hypotheses can be envisioned to explain the high frequency in Neandertals: adaptation to a specific occlusal loading regime (biomechanical advantage), adaptation to a high attrition diet, pleiotropic or genetic drift effects. In this contribution we used finite element analysis (FEA) and advanced loading concepts based on macrowear information to evaluate whether taurodontism supplies some dental biomechanical advantages. Loads were applied to the digital model of the lower right first molar (RM1) of the Neandertal specimen Le Moustier 1, as well as to the digital models of both a shortened and a hyper-taurodontic version of Le Moustier RM1. Moreover, we simulated a scenario where an object is held between teeth and pulled in different directions to investigate whether taurodontism might be useful for para-masticatory activities. Our results do not show any meaningful difference among all the simulations, pointing out that taurodontism does not improve the functional biomechanics of the tooth and does not favour para-masticatory pulling activities. Therefore, taurodontism should be considered either an adaptation to a high attrition diet or most likely the result of pleiotropic or genetic drift effects. Finally, our results have important implications for modern dentistry during endodontic treatments, as we observed that filling the pulp chamber with dentine-like material increases tooth stiffness, and ultimately tensile stresses in the crown, thus favouring tooth failure. PMID:25407030

  14. Multiscale modeling methods in biomechanics.

    Science.gov (United States)

    Bhattacharya, Pinaki; Viceconti, Marco

    2017-01-19

    More and more frequently, computational biomechanics deals with problems where the portion of physical reality to be modeled spans over such a large range of spatial and temporal dimensions, that it is impossible to represent it as a single space-time continuum. We are forced to consider multiple space-time continua, each representing the phenomenon of interest at a characteristic space-time scale. Multiscale models describe a complex process across multiple scales, and account for how quantities transform as we move from one scale to another. This review offers a set of definitions for this emerging field, and provides a brief summary of the most recent developments on multiscale modeling in biomechanics. Of all possible perspectives, we chose that of the modeling intent, which vastly affect the nature and the structure of each research activity. To the purpose we organized all papers reviewed in three categories: 'causal confirmation,' where multiscale models are used as materializations of the causation theories; 'predictive accuracy,' where multiscale modeling is aimed to improve the predictive accuracy; and 'determination of effect,' where multiscale modeling is used to model how a change at one scale manifests in an effect at another radically different space-time scale. Consistent with how the volume of computational biomechanics research is distributed across application targets, we extensively reviewed papers targeting the musculoskeletal and the cardiovascular systems, and covered only a few exemplary papers targeting other organ systems. The review shows a research subdomain still in its infancy, where causal confirmation papers remain the most common. For further resources related to this article, please visit the WIREs website.

  15. Biomechanical properties of four dermal substitutes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guo-an; NING Fang-gang; ZHAO Nan-ming

    2007-01-01

    @@ Many kinds of cell-free dermal substitutes have been developed during the past several years, however,their biomechanical properties, including hysteresis,stress relaxation, creep, and non-linear stress-strain, are still unknown. In this study, we tested these biomechanical characteristics of four dermal substitutes,and compared them with those of fresh human skin (FHS).

  16. Applied Biomechanics in an Instructional Setting

    Science.gov (United States)

    Hudson, Jackie L.

    2006-01-01

    Biomechanics is the science of how people move better, meaning more skillfully and more safely. This article places more emphasis on skill rather than safety, though there are many parallels between them. It shares a few features of the author's paradigm of applied biomechanics and discusses an integrated approach toward a middle school football…

  17. Osteoplastic maxillotomy approach for infraorbital nerve schwannoma, a case report.

    Science.gov (United States)

    Karkas, Alexandre A; Schmerber, Sébastien A; Bettega, Georges V; Reyt, Emile P; Righini, Christian A

    2008-03-01

    Extracranial schwannomas can readily occur in the head and neck region and rarely involve the trigeminal nerve. As a rule, their treatment is surgical and dictated by the location of the tumor and nerve of origin. We describe a case of a 14-year-old boy with a mass invading right nasal fossa, maxillary sinus, orbital floor, pterygopalatine fossa, and infratemporal fossa. The diagnosis of a nerve sheath tumor was evoked after angiography showed no vascular blush. The tumor was removed through a Weber-Fergusson incision with subciliary extension followed by maxillozygomatic osteotomy. This approach showed the tumor to be coming from the infraorbital nerve and allowed complete tumor exposure and removal. Pathology confirmed the diagnosis of a schwannoma. We describe the osteoplastic maxillotomy approach which we felt most appropriate for removal of the infraorbital schwannoma and discuss other possible surgical options for this type of tumor. (c) 2007 Wiley Periodicals, Inc. Head Neck 2008.

  18. Perineural tumor spread - Interconnection between spinal and cranial nerves.

    Science.gov (United States)

    Kozić, Duško; Njagulj, Vesna; Gaćeša, Jelena Popadić; Semnic, Robert; Prvulović, Nataša

    2012-12-15

    The secondary neoplastic involvement of the cervical plexus in patients with head and neck malignancies is extremely rare. MR examination of the neck revealed the diffuse neoplastic infiltration of the right C2 root, in a 57-year-old patient with several months long pain in the right ear region and a history of the tongue squamous cell carcinoma. Associated perineural tumor spread and consequent distal involvement of great auricular nerve and vagus nerve were evident. Best of our knowledge, this is the first reported involvement of the cervical plexus in patients with head and neck cancers, associated with the clearly documented interconnection between the cervical plexus and cranial nerves via great auricular nerve.

  19. Problems of Sport Biomechanics and Robotics

    Directory of Open Access Journals (Sweden)

    Wlodzimierz S. Erdmann

    2013-02-01

    Full Text Available This paper presents many common areas of interest of different specialists. There are problems described from sport, biomechanics, sport biomechanics, sport engineering, robotics, biomechanics and robotics, sport biomechanics and robotics. There are many approaches to sport from different sciences and engineering. Robotics is a relatively new area and has had moderate attention from sport specialists. The aim of this paper is to present several areas necessary to develop sport robots based on biomechanics and also to present different types of sport robots: serving balls, helping to provide sports training, substituting humans during training, physically participating in competitions, physically participating in competitions against humans, serving as models of real sport performance, helping organizers of sport events and robot toys. Examples of the application of robots in sports communities are also given.

  20. What are Head Cavities? - A History of Studies on Vertebrate Head Segmentation.

    Science.gov (United States)

    Kuratani, Shigeru; Adachi, Noritaka

    2016-06-01

    Motivated by the discovery of segmental epithelial coeloms, or "head cavities," in elasmobranch embryos toward the end of the 19th century, the debate over the presence of mesodermal segments in the vertebrate head became a central problem in comparative embryology. The classical segmental view assumed only one type of metamerism in the vertebrate head, in which each metamere was thought to contain one head somite and one pharyngeal arch, innervated by a set of cranial nerves serially homologous to dorsal and ventral roots of spinal nerves. The non-segmental view, on the other hand, rejected the somite-like properties of head cavities. A series of small mesodermal cysts in early Torpedo embryos, which were thought to represent true somite homologs, provided a third possible view on the nature of the vertebrate head. Recent molecular developmental data have shed new light on the vertebrate head problem, explaining that head mesoderm evolved, not by the modification of rostral somites of an amphioxus-like ancestor, but through the polarization of unspecified paraxial mesoderm into head mesoderm anteriorly and trunk somites posteriorly.

  1. The validation and application of a finite element human head model for frontal skull fracture analysis.

    Science.gov (United States)

    Asgharpour, Z; Baumgartner, D; Willinger, R; Graw, M; Peldschus, S

    2014-05-01

    Traumatic head injuries can result from vehicular accidents, sports, falls or assaults. The current advances in computational methods and the detailed finite element models of the human head provide a significant opportunity for biomechanical study of human head injuries. The biomechanical characteristics of the human head through head impact scenarios can be studied in detail by using the finite element models. Skull fracture is one of the most frequent occurring types of head injuries. The purpose of this study is to analyse the experimental head impacts on cadavers by means of the Strasbourg University Finite Element Head Model (SUFEHM). The results of the numerical model and experimental data are compared for validation purpose. The finite element model has also been applied to predict the skull bone fracture in frontal impacts. The head model includes the scalp, the facial bone, the skull, the cerebral spinal fluid, the meninges, the cerebrum and the cerebellum. The model is used to simulate the experimental frontal head impact tests using a cylindrical padded impactor. Results of the computational simulation shows that the model correlated well with a number of experimental data and a global fracture pattern has been predicted well by the model. Therefore the presented numerical model could be used for reconstruction of head impacts in different impact conditions also the forensic application of the head model would provide a tool for investigation of the causes and mechanism of head injuries.

  2. BRAIN INJURY BIOMECHANICS IN REAL WORLD VEHICLE ACCIDENT USING MATHEMATICAL MODELS

    Institute of Scientific and Technical Information of China (English)

    YANG Jikuang; XU Wei; OTTE Dietmar

    2008-01-01

    This paper aims at investigating brain injury mechanisms and predicting head injuries in real world accidents. For this purpose, a 3D human head finite element model (HBM-head) was developed based on head-brain anatomy. The HBM head model was validated with two experimental tests. Then the head finite element(FE) model and a multi-body system (MBS) model were used to carry out reconstructions of real world vehicle-pedestrian accidents and brain injuries. The MBS models were used for calculating the head impact conditions in vehicle impacts. The HBM-head model was used for calculating the injury related physical parameters, such as intracranial pressure, stress, and strain. The calculated intracranial pressure and strain distribution were correlated with the injury outcomes observed from accidents. It is shown that this model can predict the intracranial biomechanical response and calculate the injury related physical parameters. The head FE model has good biofidelity and will be a valuable tool for the study of injury mechanisms and the tolerance level of the brain.

  3. A comparison in a youth population between those with and without a history of concussion using biomechanical reconstruction.

    Science.gov (United States)

    Post, Andrew; Hoshizaki, T Blaine; Gilchrist, Michael D; Koncan, David; Dawson, Lauren; Chen, Wesley; Ledoux, Andrée-Anne; Zemek, Roger

    2017-04-01

    OBJECTIVE Concussion is a common topic of research as a result of the short- and long-term effects it can have on the affected individual. Of particular interest is whether previous concussions can lead to a biomechanical susceptibility, or vulnerability, to incurring further head injuries, particularly for youth populations. The purpose of this research was to compare the impact biomechanics of a concussive event in terms of acceleration and brain strains of 2 groups of youths: those who had incurred a previous concussion and those who had not. It was hypothesized that the youths with a history of concussion would have lower-magnitude biomechanical impact measures than those who had never suffered a previous concussion. METHODS Youths who had suffered a concussion were recruited from emergency departments across Canada. This pool of patients was then separated into 2 categories based on their history of concussion: those who had incurred 1 or more previous concussions, and those who had never suffered a concussion. The impact event that resulted in the brain injury was reconstructed biomechanically using computational, physical, and finite element modeling techniques. The output of the events was measured in biomechanical parameters such as energy, force, acceleration, and brain tissue strain to determine if those patients who had a previous concussion sustained a brain injury at lower magnitudes than those who had no previously reported concussion. RESULTS The results demonstrated that there was no biomechanical variable that could distinguish between the concussion groups with a history of concussion versus no history of concussion. CONCLUSIONS The results suggest that there is no measureable biomechanical vulnerability to head impact related to a history of concussions in this youth population. This may be a reflection of the long time between the previous concussion and the one reconstructed in the laboratory, where such a long period has been associated with

  4. Optic nerve oxygenation

    DEFF Research Database (Denmark)

    Stefánsson, Einar; Pedersen, Daniella Bach; Jensen, Peter Koch

    2005-01-01

    at similar levels of perfusion pressure. The levels of perfusion pressure that lead to optic nerve hypoxia in the laboratory correspond remarkably well to the levels that increase the risk of glaucomatous optic nerve atrophy in human glaucoma patients. The risk for progressive optic nerve atrophy in human...... glaucoma patients is six times higher at a perfusion pressure of 30 mmHg, which corresponds to a level where the optic nerve is hypoxic in experimental animals, as compared to perfusion pressure levels above 50 mmHg where the optic nerve is normoxic. Medical intervention can affect optic nerve oxygen......-oxygenase inhibitor, indomethacin, which indicates that prostaglandin metabolism plays a role. Laboratory studies suggest that carbonic anhydrase inhibitors might be useful for medical treatment of optic nerve and retinal ischemia, potentially in diseases such as glaucoma and diabetic retinopathy. However, clinical...

  5. Optic nerve oxygenation

    DEFF Research Database (Denmark)

    Stefánsson, Einar; Pedersen, Daniella Bach; Jensen, Peter Koch;

    2005-01-01

    at similar levels of perfusion pressure. The levels of perfusion pressure that lead to optic nerve hypoxia in the laboratory correspond remarkably well to the levels that increase the risk of glaucomatous optic nerve atrophy in human glaucoma patients. The risk for progressive optic nerve atrophy in human...... glaucoma patients is six times higher at a perfusion pressure of 30 mmHg, which corresponds to a level where the optic nerve is hypoxic in experimental animals, as compared to perfusion pressure levels above 50 mmHg where the optic nerve is normoxic. Medical intervention can affect optic nerve oxygen......-oxygenase inhibitor, indomethacin, which indicates that prostaglandin metabolism plays a role. Laboratory studies suggest that carbonic anhydrase inhibitors might be useful for medical treatment of optic nerve and retinal ischemia, potentially in diseases such as glaucoma and diabetic retinopathy. However, clinical...

  6. Biomechanical performance of orthopedic gloves.

    Science.gov (United States)

    Jackson, E M; Neal, J G; Williams, F M; Stern, C A; Suber, F; Thacker, J G; Edlich, R F

    1999-01-01

    The purpose of this study was to compare the biomechanical performance of commercially available orthopedic gloves to that of a single surgical glove, as well as a double glove system. The orthopedic gloves were found to be thicker than the single surgical glove. This increased thickness of the orthopedic glove was associated with a greater resistance to glove puncture. The thickest orthopedic gloves also had reduced tactile sensitivity when compared to the single surgical glove. In addition, the glove donning forces and glove hydration rates varied considerably. These latter biomechanical performance parameters were not significantly related to glove thickness. The double glove systems tested in this study had similar performance characteristics in regard to many of the orthopedic gloves. The glove donning forces for the double glove systems were the lowest of the gloves tested. In addition, the double glove systems displayed the greatest resistance to glove hydration of the gloves tested. Their performance in the glove hydration tests and the force required to don the double glove systems were much more desirable than any of the orthopedic gloves. The results of this study indicate that the double glove systems may provide a desirable alternative to the use of the single orthopedic gloves.

  7. 视频头脉冲试验评估突发性聋伴眩晕患者的前庭上下神经损伤范围%Evaluation of the injured range of vestibular superior and inferior nerves in sudden deafness patients with vertigo using video head impulse test

    Institute of Scientific and Technical Information of China (English)

    侯凌霄; 陈太生; 徐开旭; 王巍; 李姗姗; 刘强; 温超; 程岩; 赵晖

    2015-01-01

    目的 探讨视频头脉冲试验(video head impulse test,vHIT)在评估突发性聋伴眩晕患者前庭上下神经功能中的应用价值.方法 健康志愿者60例(120耳)为对照组,突聋伴眩晕患者182例(182耳)为实验组.对照组仅进行vHIT检查,实验组行vHIT和冷热试验检查;以vHIT的增益(video head impulse test-gain,vHIT-G)和冷热试验诱发眼震的非对称值(unilateral weakness,UW)作为观察指标,评估前庭上、下神经属区的功能,应用SPSS17.0统计软件进行数据分析.结果 对照组双侧前、水平和后半规管平均vHIT-G分别为(15.20±11.00)%、(15.30±13.30)%和(15.15±14.72)%,均呈正态分布,方差分析,相互间差异无统计学意义(F =0.005,P=1.000).突聋伴眩晕患者(实验组)患耳前、水平和后半规管平均vHIT-G分别为(21.73±14.84)%、(21.20±28.24)%和(19.22±23.50)%,与对照组相应半规管vHIT-G比较,差异均有统计学意义(P值均<0.05).实验组vHIT与冷热试验的阳性率分别为26.9%(49/182)和70.3%(128/182),两者比较,差异有统计学意义(P<0.05).根据vHIT结果判定,前庭上、下神经区均受累者15例(8.2%),单纯前庭上神经区受累19例(10.4%),单纯前庭下神经区受累15例(8.2%);而结合冷热试验结果综合判定,前庭上、下神经区均受累者29例(15.9%),单纯前庭上神经区受累101例(55.5%),单纯前庭下神经区受累1例(0.5%).结论 vHIT可以分别测评六个半规管的高频区功能,反映前庭上、下神经属区的高频病损情况,结合冷热试验可以更加全面地评估突聋伴眩晕患者的前庭损伤范围.%Objective To discuss the video head impulse tests (vHIT) application values in assessment of the vestibular nerves,function in sudden deafness patients with vertigo.Methods There were 60 cases(120 ears) of healthy volunteers as control group,and 182 cases(182 ears) of sudden deafness with vertigo patients as study group.The study group received

  8. Analysing physical fitness and biomechanical factors that determine tennis serve performance

    Directory of Open Access Journals (Sweden)

    Ertuğrul Gelen

    2009-11-01

    Full Text Available Normal 0 21 false false false TR X-NONE X-NONE MicrosoftInternetExplorer4 The purpose of the study is to analyse the fitness and the biomechanical factors which determine the velocity of the ball during serve in tennis (VBTS. The subjects of the study were fifteen male tournament level tennis player between the ages of sixteen and twenty five (18,8 ± 2,70 age/year. The physical fitness measurement of the study were; length, body weight, skinfold, diameter, circumference and length of the body, body composition, isometric handgrip strength, vertical jump, upper extremity range of motion (ROM and isokinetic strength. The angular velocity of racket head, racket handhold, middle finger, wrist, elbow, shoulder and hip joints on three axis during serve shoot were used for the biomechanical measurement.  The relationship between VBTS with physical fitness and biomechanical factors were measured with Pearson Correlation. The analysis showed that there was significant positive relation between VBTS and length, negative relation with mesomorphy; positive relation between ROM of shoulder dominant internal and external rotation, trunk hyper-extension, left lateral flexion and right rotation, negative relation in dominant wrist flexion, positive relation between isokinetic strength characteristics such as shoulder and elbow extension, shoulder internal and external rotation, wrist flexion, handgrip isometric strength, also in biomechanical measures, positive relation between in Y axis elbow, wrist, finger and head of the racket. As a result, fitness and biomechanical parameters that are intensively used in tennis determine VBTS. We think trainers may speed up VBTS by improved parameters and accelerated training programmes.

  9. Acute sixth nerve palsy in a young man, beware of the 'red herring'.

    LENUS (Irish Health Repository)

    O'Neill, E C

    2012-02-01

    BACKGROUND: Cranial nerve palsies has several etiologies including vascular insufficiency, neoplasm, trauma and inflammation. Isolated sixth nerve palsy is an extremely rare presenting feature of leukemia. AIM: We describe an unusual ocular presentation of a bilateral progressive sixth nerve palsy in a young male with a preceding head injury. CONCLUSION: Acquired sixth nerve palsies in young adults may be due to trauma but in the absence of a definitive history other systemic processes must be outruled. We describe a case of bilateral sixth nerve palsy in a patient with ALL with no obvious CNS involvement. Potential etiological mechanisms are discussed.

  10. Pseudoradial Nerve Palsy Caused by Acute Ischemic Stroke

    Directory of Open Access Journals (Sweden)

    Hassan Tahir MD

    2016-07-01

    Full Text Available Pseudoperipheral palsy has been used to characterize isolated monoparesis secondary to stroke. Isolated hand nerve palsy is a rare presentation for acute cerebral stroke. Our patient presented with clinical features of typical peripheral radial nerve palsy and a normal computed tomography scan of the head, which, without a detailed history and neurological examination, could have been easily misdiagnosed as a peripheral nerve lesion deferring further investigation for a stroke. We stress the importance of including cerebral infarction as a critical differential diagnosis in patients presenting with sensory-motor deficit in an isolated peripheral nerve pattern. A good history and physical exam can differentiate stroke from peripheral neuropathy as the cause of radial nerve palsy.

  11. Anatomical Characteristics and Biomechanical Properties of the Oblique Popliteal Ligament

    Science.gov (United States)

    Wu, Xiang-Dong; Yu, Jin-Hui; Zou, Tao; Wang, Wei; LaPrade, Robert F.; Huang, Wei; Sun, Shan-Quan

    2017-01-01

    This anatomical study sought to investigate the morphological characteristics and biomechanical properties of the oblique popliteal ligament (OPL). Embalmed cadaveric knees were used for the study. The OPL and its surrounding structures were dissected; its morphology was carefully observed, analyzed and measured; its biomechanical properties were investigated. The origins and insertions of the OPL were relatively similar, but its overall shape was variable. The OPL had two origins: one originated from the posterior surface of the posteromedial tibia condyle, merged with fibers from the semimembranosus tendon, the other originated from the posteromedial part of the capsule. The two origins converged and coursed superolaterally, then attached to the fabella or to the tendon of the lateral head of the gastrocnemius and blended with the posterolateral joint capsule. The OPL was classified into Band-shaped, Y-shaped, Z-shaped, Trident-shaped, and Complex-shaped configurations. The mean length, width, and thickness of the OPL were 39.54, 22.59, and 1.44 mm, respectively. When an external rotation torque (18 N·m) was applied both before and after the OPL was sectioned, external rotation increased by 8.4° (P = 0.0043) on average. The OPL was found to have a significant role in preventing excessive external rotation and hyperextension of the knee. PMID:28205540

  12. Imaging the trigeminal nerve

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Alexandra [Radiology Department, Instituto Portugues de Oncologia Francisco Gentil, Centro de Lisboa, Rua Prof. Lima Basto, 1093, Lisboa (Portugal)], E-mail: borgalexandra@gmail.com; Casselman, Jan [Department of Radiology, A. Z. St Jan Brugge and A. Z. St Augustinus Antwerpen Hospitals (Belgium)

    2010-05-15

    Of all cranial nerves, the trigeminal nerve is the largest and the most widely distributed in the supra-hyoid neck. It provides sensory input from the face and motor innervation to the muscles of mastication. In order to adequately image the full course of the trigeminal nerve and its main branches a detailed knowledge of neuroanatomy and imaging technique is required. Although the main trunk of the trigeminal nerve is consistently seen on conventional brain studies, high-resolution tailored imaging is mandatory to depict smaller nerve branches and subtle pathologic processes. Increasing developments in imaging technique made possible isotropic sub-milimetric images and curved reconstructions of cranial nerves and their branches and led to an increasing recognition of symptomatic trigeminal neuropathies. Whereas MRI has a higher diagnostic yield in patients with trigeminal neuropathy, CT is still required to demonstrate the bony anatomy of the skull base and is the modality of choice in the context of traumatic injury to the nerve. Imaging of the trigeminal nerve is particularly cumbersome as its long course from the brainstem nuclei to the peripheral branches and its rich anastomotic network impede, in most cases, a topographic approach. Therefore, except in cases of classic trigeminal neuralgia, in which imaging studies can be tailored to the root entry zone, the full course of the trigeminal nerve has to be imaged. This article provides an update in the most recent advances on MR imaging technique and a segmental imaging approach to the most common pathologic processes affecting the trigeminal nerve.

  13. Porcine head response to blast

    Directory of Open Access Journals (Sweden)

    Jay eShridharani

    2012-05-01

    Full Text Available Recent studies have shown an increase in the frequency of traumatic brain injuries related to blast exposure. However, the mechanisms that cause blast neurotrauma are unknown. Blast neurotrauma research using computational models has been one method to elucidate that response of the brain in blast, and to identify possible mechanical correlates of injury. However, model validation against experimental data is required to ensure that the model output is representative of in vivo biomechanical response. This study exposed porcine subjects to primary blast overpressures generated using a compressed-gas shock tube. Shock tube blasts were directed to the unprotected head of each animal while the lungs and thorax were protected using ballistic protective vests similar to those employed in theater. The test conditions ranged from 110-740 kPa peak incident overpressure with scaled durations from 1.3-6.9 ms and correspond approximately with a 50% injury risk for brain bleeding and apnea in a ferret model scaled to porcine exposure. The bulk head acceleration and the pressure at the surface of the head and in the cranial cavity were measured. Immediately after the blast, 5 of the 20 animals tested were apneic. Three subjects recovered without intervention within thirty seconds and the remaining two recovered within 8 minutes following bagging and administration of the respiratory stimulant doxapram. Gross examination of the brain revealed no indication of bleeding. Intracranial pressures ranged from 80-685 kPa as a result of the blast and were notably lower than the shock tube reflected pressures of 300-2830 kPa, indicating pressure attenuation by the skull up to a factor of 8.4. Peak head accelerations were measured from 385-3845 G’s and were well correlated with peak incident overpressure (R2=0.90. One standard deviation corridors for the surface pressure, intracranial pressure, and head acceleration are presented to provide experimental data for

  14. Preventing head and neck injury.

    Science.gov (United States)

    McIntosh, A S; McCrory, P

    2005-06-01

    A wide range of head and neck injury risks are present in sport, including catastrophic injury. The literature since 1980 on prevention of head and neck injury in sport was reviewed, focusing on catastrophic and brain injury and identifying the range of injury prevention methods in use. There have been few formal evaluations of injury prevention methods. Approaches that are considered, or have been proven, to be successful in preventing injury include: modification of the baseball; implementation of helmet standards in ice hockey and American football and increased wearing rates; use of full faceguards in ice hockey; changes in rules associated with body contact; implementation of rules to reduce the impact forces in rugby scrums. Helmets and other devices have been shown to reduce the risk of severe head and facial injury, but current designs appear to make little difference to rates of concussion. Research methods involving epidemiological, medical, and human factors are required in combination with biomechanical and technological approaches to reduce further injury risks in sport.

  15. Head Start.

    Science.gov (United States)

    Greenman, Geri

    2000-01-01

    Discusses an art project in which students created drawings of mop heads. Explains that the approach of drawing was more important than the subject. States that the students used the chiaroscuro technique, used by Rembrandt and Caravaggio, in which light appears out of the darkness. (CMK)

  16. Endocrine tumors associated with the vagus nerve.

    Science.gov (United States)

    Varoquaux, Arthur; Kebebew, Electron; Sebag, Fréderic; Wolf, Katherine; Henry, Jean-François; Pacak, Karel; Taïeb, David

    2016-09-01

    The vagus nerve (cranial nerve X) is the main nerve of the parasympathetic division of the autonomic nervous system. Vagal paragangliomas (VPGLs) are a prime example of an endocrine tumor associated with the vagus nerve. This rare, neural crest tumor constitutes the second most common site of hereditary head and neck paragangliomas (HNPGLs), most often in relation to mutations in the succinate dehydrogenase complex subunit D (SDHD) gene. The treatment paradigm for VPGL has progressively shifted from surgery to abstention or therapeutic radiation with curative-like outcomes. Parathyroid tissue and parathyroid adenoma can also be found in close association with the vagus nerve in intra or paravagal situations. Vagal parathyroid adenoma can be identified with preoperative imaging or suspected intraoperatively by experienced surgeons. Vagal parathyroid adenomas located in the neck or superior mediastinum can be removed via initial cervicotomy, while those located in the aortopulmonary window require a thoracic approach. This review particularly emphasizes the embryology, molecular genetics, and modern imaging of these tumors.

  17. Biomechanics and analysis of running gait.

    Science.gov (United States)

    Dugan, Sheila A; Bhat, Krishna P

    2005-08-01

    Physical activity, including running, is important to general health by way of prevention of chronic illnesses and their precursors. To keep runners healthy, it is paramount that one has sound knowledge of the biomechanics of running and assessment of running gait. More so, improving performance in competitive runners is based in sound training and rehabilitation practices that are rooted firmly in biomechanical principles. This article summarized the biomechanics of running and the means with which one can evaluate running gait. The gait assessment techniques for collecting and analyzing kinetic and kinematic data can provide insights into injury prevention and treatment and performance enhancement.

  18. Biomechanical performance of leather and modern football helmets.

    Science.gov (United States)

    Rowson, Steven; Daniel, Ray W; Duma, Stefan M

    2013-09-01

    With the increased national concern about concussions in football, recent research has focused on evaluating the impact performance of modern football helmets. Specifically, this technical note offers a biomechanical analysis of classic leather helmets compared with modern helmets. Furthermore, modern helmets were examined to illustrate the performance differences between the better- and worse-performing ones. A total of 1224 drop tests were performed from a range of drop heights and impact locations on 11 different helmet types (10 modern and 1 leather helmet model). The resulting head acceleration was used to assess the risk of concussion for each drop test. The results of this analysis demonstrate that modern helmets are significantly and substantially superior to leather helmets in all impact scenarios, and that notable differences exist among modern helmets.

  19. Biomechanical analysis of injury criterion for child and adult dummies.

    Science.gov (United States)

    Sances, A

    2000-01-01

    The development of human injury tolerance is difficult because of the physical differences between humans and animals, the available dummies, and tissue of the cadaver. Furthermore, human volunteer testing can clearly only be done at subinjurious levels. While considerable biomechanical injury evidence exists for the adult human based on cadaveric studies, little information is available for the pediatric population. However, some material is available from skull bone modulus studies and from the fetal tendon strength and early pediatric studies of the newborn. A review of living human, animal, and human cadaveric studies, which forms the basis for head-neck injury criterion are given. Examples of the use of the Hybrid III dummy for injury prediction such as in the Malibu rollover tests and air bag mechanisms show neck injury levels are considerably above the proposed Malibu 2000 N level.

  20. Nerve conduction and excitability studies in peripheral nerve disorders

    DEFF Research Database (Denmark)

    Krarup, Christian; Moldovan, Mihai

    2009-01-01

    PURPOSE OF REVIEW: The review is aimed at providing information about the role of nerve excitability studies in peripheral nerve disorders. It has been known for many years that the insight into peripheral nerve pathophysiology provided by conventional nerve conduction studies is limited. Nerve...

  1. Potassium titanyl phosphate laser welding following complete nerve transection.

    Science.gov (United States)

    Bhatt, Neel K; Mejias, Christopher; Kallogjeri, Dorina; Gale, Derrick C; Park, Andrea M; Paniello, Randal C

    2017-07-01

    Cranial nerve transection during head and neck surgery is conventionally repaired by microsuture reanastomosis. Laser nerve welding (LNW), using CO2 laser to spot-weld the epineurium of transected nerve endings, has been shown in animal models to be a novel alternative to microsuture repair. This method avoids needle/suture material and minimizes instrumentation of the nerve. We hypothesized that potassium titanyl phosphate (KTP) laser would be superior to CO2 laser in repairing transected nerves. Using a rat posterior tibial nerve injury model, we compared CO2 laser, KTP laser, and microsuture reanastomosis. Animal study. Animals underwent unilateral posterior tibial nerve transection. The injury was repaired by microsuture repair (n = 15), CO2 laser repair (n = 15), or KTP laser repair (n = 15). Weekly walking tracks were performed to measure functional recovery. Nerve segments were harvested for axon counting. At 6 weeks, the KTP LNW had the best functional recovery (92.4 ± 8.6%) compared to microsuture repair (84.5 ± 10.2%, difference 7.9%, 95% confidence interval [CI]: 0.84%-14.96%). CO2 laser repair had a functional recovery of 86.8 ± 11.2%. KTP LNW had better axon recovery compared to transection/repair (difference 530.7 axons, 95% CI: 329.9-731.5). Operative time for the microsuture repair was 18.2 ± 6.8 minutes, compared to 5.8 ± 3.7 minutes for the LNW groups (difference 12.4 minutes, 95% CI: 8.6-16.2 minutes). KTP, CO2 , and microsuture repair all showed good functional recovery following complete transection of the posterior tibial nerve. Following complete nerve transection during head and neck surgery, KTP LNW may be a novel alternative to microsuture repair. NA Laryngoscope, 127:1525-1530, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

  2. Developmental biomechanics of neck musculature.

    Science.gov (United States)

    Lavallee, Amy V; Ching, Randal P; Nuckley, David J

    2013-02-01

    Neck mechanics is central to head injury prevention since it is the musculoskeletal neck, which dictates the position and movement of the head. In the US, traumatic injury is the leading cause of death for children; however prevention is hampered by the lack of data concerning the mechanics of the immature head-and-neck. Thus, the objective of this study was to quantify neck muscle strength and endurance across the maturation spectrum and correlate these with head-and-neck anthropometry. A factorial study was performed on 91 human subjects measuring head-and-neck anthropometry and neck strength and endurance in three bending directions (flexion, extension, and lateral) as a function of age (6-23 years). Using a custom device, neck maximum voluntary contraction (MVC) force was measured in triplicate. Next, neck muscle endurance (sustained effort) was measured as the subjects' ability to maintain 70% of peak force over 30s. Linear regression of peak force and endurance as a function of age revealed each direction to significantly (pNeck muscle strength, similar between young males and females, becomes disparate in adolescence and adulthood with males exhibiting greater strength. Bending direction differences were also found with extension strength being the greatest regardless of age and sex. Furthermore, neck circumference appears predictive of neck strength and endurance in children. Together, these relationships may facilitate improved design of injury prevention interventions.

  3. Biomechanics of knife stab attacks.

    Science.gov (United States)

    Chadwick, E K; Nicol, A C; Lane, J V; Gray, T G

    1999-10-25

    Equipment, materials and methods for the measurement of the biomechanical parameters governing knife stab attacks have been developed and data have been presented that are relevant to the improvement of standards for the testing of stab-resistant materials. A six-camera Vicon motion analysis system was used to measure velocity, and derive energy and momentum during the approach phase of the attack and a specially developed force-measuring knife was used to measure three-dimensional forces and torque during the impact phase. The body segments associated with the knife were modelled as a series of rigid segments: trunk, upper arm, forearm and hand. The velocities of these segments, together with knowledge of the mass distribution from biomechanical tables, allowed the calculation of the individual segment energy and momentum values. The instrumented knife measured four components of load: axial force (along the length of the blade), cutting force (parallel to the breadth of the blade), lateral force (across the blade) and torque (twisting action) using foil strain gauges. Twenty volunteers were asked to stab a target with near maximal effort. Three styles of stab were used: a short thrust forward, a horizontal style sweep around the body and an overhand stab. These styles were chosen based on reported incidents, providing more realistic data than had previously existed. The 95th percentile values for axial force and energy were 1885 N and 69 J, respectively. The ability of current test methods to reproduce the mechanical parameters measured in human stab attacks has been assessed. It was found that current test methods could reproduce the range of energy and force values measured in the human stab attacks, although the simulation was not accurate in some respects. Non-axial force and torque values were also found to be significant in the human tests, but these are not reproduced in the standard mechanical tests.

  4. Abducens Nerve Palsy and Ipsilateral Horner Syndrome in a Patient With Carotid-Cavernous Fistula.

    Science.gov (United States)

    Kal, Ali; Ercan, Zeynep E; Duman, Enes; Arpaci, Enver

    2015-10-01

    The combination of abducens nerve palsy and ipsilateral Horner syndrome was first described by Parkinson and considered as a localizing sign of posterior cavernous sinus lesions. The authors present a case with right abducens nerve palsy with ipsilateral Horner syndrome in a patient with carotid-cavernous fistula because of head trauma. The patient was referred to the ophthalmology clinic with diplopia complaint after suffering a head trauma during a motorcycle accident. Cerebral angiography showed low-flow carotid-cavernous fistula.

  5. Generalized mechanical pain sensitivity over nerve tissues in patients with strictly unilateral migraine.

    Science.gov (United States)

    Fernández-de-las-Peñas, César; Arendt-Nielsen, Lars; Cuadrado, María Luz; Pareja, Juan A

    2009-06-01

    No study has previously analyzed pressure pain sensitivity of nerve trunks in migraine. This study aimed to examine the differences in mechanical pain sensitivity over specific nerves between patients with unilateral migraine and healthy controls. Blinded investigators assessed pressure pain thresholds (PPT) over the supra-orbital nerves (V1) and peripheral nerve trunks of both upper extremities (median, radial, and ulnar nerves) in 20 patients with strictly unilateral migraine and 20 healthy matched controls. Pain intensity after palpation over both supra-orbital nerves was also assessed. A pressure algometer was used to quantify PPT, whereas a 10-point numerical pain rate scale was used to evaluate pain to palpation over the supra-orbital nerve. The analysis of covariance revealed that pain to palpation over the supra-orbital nerve was significantly higher (P0.6). In patients with unilateral migraine, we found increased mechano-sensitivity of the supra-orbital nerve on the symptomatic side of the head. Outside the head, the same patients showed increased mechano-sensitivity of the main peripheral nerves of both upper limbs, without asymmetries. Such diffuse hypersensitivity of the peripheral nerves lends further evidence to the presence of a state of hyperexcitability of the central nervous system in patients with unilateral migraine.

  6. Large Extremity Peripheral Nerve Repair

    Science.gov (United States)

    2016-12-01

    Photochemical bond- ing required clear access 5 mm proximal and dis- tal to coaptation sites. As a result, the maximum achievable nerve gap before...rodents for nerve gap reconstruction. Induction and maintenance anesthesia was achieved using isoflurane (Baxter Healthcare Corp., Deerfield, Ill...injury, nerve gap , nerve wrap, PTB, photosealing, Rose Bengal, amnion, nerve conduit, crosslinking, allograft, photochemistry. 3. Accomplishments

  7. Axillary nerve conduction changes in hemiplegia

    Directory of Open Access Journals (Sweden)

    Ring Haim

    2008-12-01

    Full Text Available Abstract Aim To prove the possibility of axillary nerve conduction changes following shoulder subluxation due to hemiplegia, in order to investigate the usefulness of screening nerve conduction studies in patients with hemiplegia for finding peripheral neuropathy. Methods Forty-four shoulders of twenty-two patients with a first-time stroke having flaccid hemiplegia were tested, 43 ± 12 days after stroke onset. Wasting and weakness of the deltoid were present in the involved side. Motor nerve conduction latency and compound muscle action potential (CMAP amplitude were measured along the axillary nerve, comparing the paralyzed to the sound shoulder. The stimulation was done at the Erb's point whilst the recording needle electrode was inserted into the deltoid muscle 4 cm directly beneath the lateral border of the acromion. Wilcoxon signed rank test was used to compare the motor conduction between the sound and the paralytic shoulder. Mann-Whitney test was used to compare between plegic and sound shoulder in each side. Results Mean motor nerve conduction latency time to the deltoid muscle was 8.49, SD 4.36 ms in the paralyzed shoulder and 5.17, SD 1.35 ms in the sound shoulder (p Mean compound muscle action potential (CMAP amplitude was 2.83, SD 2.50 mV in the paralyzed shoulder and was 7.44, SD 5.47 mV in the sound shoulder (p p p = 0.003, 1-sided for amplitude, and patients with left paralyzed shoulder compared to patients with left sound shoulder (p = 0.011, 1-sided for latency, p = 0.001, 1-sided for amplitude, support the same outcomes. The electro-physiological changes in the axillary nerve may appear during the first six weeks after stroke breakout. Conclusion Continuous traction of the axillary nerve, as in hypotonic shoulder, may affect the electro-physiological properties of the nerve. It most probably results from subluxation of the head of the humerus, causing demyelinization and even axonopathy. Slowing of the conduction velocities of

  8. Pulsed radiofrequency application in the entrapment neuropathy of a sural nerve.

    Science.gov (United States)

    Gozdemir, Muhammet; Usta, Burhanettin; Sert, Huseyin; Muslu, Bunyamin; Demircioglu, Irem Ruveyda; Uras, Ismail

    2010-04-01

    Compressive and entrapment neuropathy of the peroneal nerve is the most common entrapment syndrome in the lower limbs, often caused by mechanical or dynamic compression of a segment of nerve at the level of the fibula head. Because of its special anatomic situation, external compression while under trauma or traction is quite easy. A case of entrapment neuropathy syndrome in a 33-year-old man treated by pulse radiofrequency to the lateral cutaneous branch of the common peroneal nerve is presented.

  9. Pulsed Radiofrequency Application in the Entrapment Neuropathy of a Sural Nerve

    OpenAIRE

    Gozdemir, Muhammet; Usta, Burhanettin; Sert, Huseyin; Muslu,Bunyamin; Demircioglu, Irem Ruveyda; Uras, Ismail

    2010-01-01

    Compressive and entrapment neuropathy of the peroneal nerve is the most common entrapment syndrome in the lower limbs, often caused by mechanical or dynamic compression of a segment of nerve at the level of the fibula head. Because of its special anatomic situation, external compression while under trauma or traction is quite easy. A case of entrapment neuropathy syndrome in a 33-year-old man treated by pulse radiofrequency to the lateral cutaneous branch of the common peroneal nerve is prese...

  10. THE CENTER FOR MILITARY BIOMECHANICS RESEARCH

    Data.gov (United States)

    Federal Laboratory Consortium — The Center for Military Biomechanics Research is a 7,500 ft2 dedicated laboratory outfitted with state-of-the-art equipment for 3-D analysis of movement, measurement...

  11. Biomechanics/risk management (Working Group 2)

    DEFF Research Database (Denmark)

    Sanz, Mariano; Naert, Ignace; Gotfredsen, Klaus

    2009-01-01

    INTRODUCTION: The remit of this workgroup was to update the existing knowledge base in biomechanical factors, navigation systems and medications that may affect the outcome of implant therapy. MATERIAL AND METHODS: The literature was systematically searched and critically reviewed. Five manuscrip...... were produced in five specific topics identified as areas where innovative approaches have been developed in biomechanical factors, navigation systems and medications that may affect the outcome of implant therapy. RESULTS: The results and conclusions of the review process are presented...

  12. Biomechanical study of intervertebral disc degeneration

    OpenAIRE

    González Guitiérrez, Ramiro Arturo

    2012-01-01

    Degeneration and age affect the biomechanics of the intervertebral disc, by reducing its stiffness, flexibility and shock absorption capacities against daily movement and spinal load. The biomechanical characterization of intervertebral discs is achieved by conducting mechanical testing to vertebra-disc-vertebra segments and applying axial, shear, bend and torsion loads, statically or dynamically, with load magnitudes corresponding to the physiological range. However, traditional testing does...

  13. Biomechanical study of intervertebral disc degeneration

    OpenAIRE

    González Guitiérrez, Ramiro Arturo

    2012-01-01

    Degeneration and age affect the biomechanics of the intervertebral disc, by reducing its stiffness, flexibility and shock absorption capacities against daily movement and spinal load. The biomechanical characterization of intervertebral discs is achieved by conducting mechanical testing to vertebra-disc-vertebra segments and applying axial, shear, bend and torsion loads, statically or dynamically, with load magnitudes corresponding to the physiological range. However, traditional testing does...

  14. Harnessing Biomechanics to Develop Cartilage Regeneration Strategies

    OpenAIRE

    Athanasiou, KA; Responte, DJ; Brown, WE; Hu, JC

    2015-01-01

    Copyright © 2015 by ASME. As this review was prepared specifically for the American Society of Mechanical Engineers H.R. Lissner Medal, it primarily discusses work toward cartilage regeneration performed in Dr. Kyriacos A. Athanasiou's laboratory over the past 25 years. The prevalence and severity of degeneration of articular cartilage, a tissue whose main function is largely biomechanical, have motivated the development of cartilage tissue engineering approaches informed by biomechanics. Thi...

  15. Overhead shoulder press-In-front of the head or behind the head?

    Institute of Scientific and Technical Information of China (English)

    Mark R. McKean; Brendan J. Burkett

    2015-01-01

    Background:Using a cross-sectional design comparison, two overhead press techniques (in-front of the head or behind the head) were compared. The purpose of this study was to determine the impact of behind the head or in-front of the head overhead pressing technique on shoulder range of movement (ROM) and spine posture. The overhead press is commonly prescribed exercise. The two techniques (in-front of the head or behind the head) may influence joint mechanics and therefore require an objective analysis. Methods: Passive shoulder ROM quantified using goniometric measures, dynamic ROM utilised three-dimensional (3D) biomechanical mea-sures (120 Hz) of 33 participants performing overhead pressing in a seated position. The timing and synchronisation of the upper limb shoulder and spine segments were quantified and influence of each technique was investigated. Results:The in-front technique commenced in lordotic position, whilst behind the head technique commenced in kyphotic position. Behind the head technique started with less thoracic extension than in-front condition. The thoracic spine remained extended and moved between 12° and 15° regardless of gender or technique. The techniques resulted in a significant difference between genders. Males were able to maintain a flat or normal lumbar lordosis, whereas females tended to kyphotic. Conclusion:Shoulder ROM was within passive ROM for all measures except external rotation for males with the behind the head technique. To avoid possible injury passive ROM should be increased prior to behind the head protocol. Females showed greater spine movements, suggesting trunk strengthening may assist overhead pressing techniques. For participants with normal trunk stability and ideal shoulder ROM, overhead pressing is a safe exercise (for the shoulder and spine) when performed either in-front of or behind the head.

  16. The Biomechanics of Gender Difference and Whiplash Injury: Designing Safer Car Seats for Women

    Directory of Open Access Journals (Sweden)

    J. Mordaka

    2003-01-01

    Full Text Available Female car users are reported to have a higher incidence of soft tissue neck injuries in low speed rear-end collisions than males, and they apparently take longer to recover. This paper addresses the whiplash problem by developing a biomechanical FEM (Finite Element Method model of the 50th and the 5th percentile female cervical spines, based on the earlier published male model created at the Nottingham Trent University. This model relies on grafting a detailed biomechanical model of the neck and head onto a standard HYBRID III dummy model. The overall philosophy of the investigation was to see if females responded essentially as scaled down males from the perspective of rear end collisions. It was found that detailed responses varied significantly with gender and it became clear that females cannot be modelled as scaled-down males, thus confirming the need for separate male and female biomechanical models and a revision of car test programmes and regulations which are currently based on the average male. Further investigation is needed to quantify the gender differences and then recommendations can be made for changes to the design of car seats and head restraints in order to reduce the risk of soft tissue injury to women.

  17. A biomechanical study of bankart lesion fixation - biodegradable ArthroRivet tack vs. suture repair.

    Science.gov (United States)

    Collins, Kevin J; Mukherjee, Debi P; Ogden, Alan L; Sadasivan, Kalia K; Albright, James A; Pietrzak, William S

    2007-01-01

    Bioabsorbable fixation is commonly used in soft tissue procedures performed in the shoulder. ArthroRivettrade mark tacks (referred to as rivets here), made from a copolymer of 82% poly-L-lactic acid and 18% polyglycolic acid, were developed for the Bankart procedure. Although a previous in vivo study demonstrated favorable comparison of the fixation strength and absorption characteristics of this device with that of polyglyconate bioabsorbable tacks, there have been no published biomechanical studies of this rivet in the shoulder. Fourteen shoulders were harvested from fresh-frozen cadavers of average age 74 years (46-89). Biomechanical testing was performed by measuring the energy, or work, required to anteriorly displace the humeral head 6 mm from the glenoid. Each shoulder was tested intact, vented, and before and after repair of a simulated Bankart lesion at 0, 45, and 90 degrees of abduction with and without maximal external rotation. Overall, the average work required ranged from 54.7 N-mm to 178.27 N-mm. Although the biomechanical performance of the rivet, based on resistance to anterior displacement of the humeral head, was indistinguishable from that of the suture repair, the statistical power of the test was low due to the large variance in the cadaver specimens. The results, in general, correlated well with those of previously published studies, suggesting the suitability of the bioabsorbable rivet for use in Bankart repair.

  18. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... Professions Site Index A-Z Computed Tomography (CT) - Head Computed tomography (CT) of the head uses special ... the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a CT ...

  19. Suprascapular nerve palsy.

    Science.gov (United States)

    Moskowitz, E; Rashkoff, E S

    1989-11-01

    Isolated traumatic suprascapular nerve palsy without associated fracture is a rare occurrence. Localized segmental muscle atrophy limited to the supraspinatus and infraspinatus muscles associated with weakness in initiating abduction and in external rotation of the shoulder should suggest the diagnosis. Electromyography will confirm the diagnosis by excluding nerve root and brachial plexus involvement with denervation potentials limited to the supraspinatus and infraspinatus muscles.

  20. Imaging the hypoglossal nerve

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Pedro [Department of Radiology, Centro Hospitalar de Lisboa Central-Hospital de Sao Jose, Rua Jose Antonio Serrano, 1150-199 Lisboa Codex (Portugal)], E-mail: tojais.pedro@gmail.com

    2010-05-15

    The hypoglossal nerve is a pure motor nerve. It provides motor control to the intrinsic and extrinsic tongue muscles thus being essential for normal tongue movement and coordination. In order to design a useful imaging approach and a working differential diagnosis in cases of hypoglossal nerve damage one has to have a good knowledge of the normal anatomy of the nerve trunk and its main branches. A successful imaging evaluation to hypoglossal diseases always requires high resolution studies due to the small size of the structures being studied. MRI is the preferred modality to directly visualize the nerve, while CT is superior in displaying the bony anatomy of the neurovascular foramina of the skull base. Also, while CT is only able to detect nerve pathology by indirect signs, such as bony expansion of the hypoglossal canal, MRI is able to visualize directly the causative pathological process as in the case of small tumors, or infectious/inflammatory processes affecting the nerve. The easiest way to approach the study of the hypoglossal nerve is to divide it in its main segments: intra-axial, cisternal, skull base and extracranial segment, tailoring the imaging technique to each anatomical area while bearing in mind the main disease entities affecting each segment.

  1. The neuropsychology of heading and head trauma in Association Football (soccer): a review.

    Science.gov (United States)

    Rutherford, Andrew; Stephens, Richard; Potter, Douglas

    2003-09-01

    Association Football (soccer) is the most popular and widespread sport in the world. A significant proportion of the injuries suffered in football are head injuries involving trauma to the brain. In normal play, head trauma frequently arises from collisions, but some researchers have claimed that it also may arise as a consequence of heading the ball. Although assessments based on biomechanical analyses are equivocal on the potential for brain injury due to football heading, a growing literature seems to support the claim that neuropsychological impairment results from general football play and football heading in particular. However, this review suggests a distinction is required between the neuropsychological effects of concussive and subconcussive head trauma and that all of the neuropsychological studies conducted so far suffer from methodological problems. At best, a few of these studies may be regarded as exploratory. The review concludes that presently, although there is exploratory evidence of subclinical neuropsychological impairment as a consequence of football-related concussions, there is no reliable and certainly no definitive evidence that such impairment occurs as a result of general football play or normal football heading. The neuropsychological consequences of football-related subconcussive effects await confirmatory investigation.

  2. Promising Technique for Facial Nerve Reconstruction in Extended Parotidectomy

    Directory of Open Access Journals (Sweden)

    Ithzel Maria Villarreal

    2015-11-01

    Full Text Available Introduction: Malignant tumors of the parotid gland account scarcely for 5% of all head and neck tumors. Most of these neoplasms have a high tendency for recurrence, local infiltration, perineural extension, and metastasis. Although uncommon, these malignant tumors require complex surgical treatment sometimes involving a total parotidectomy including a complete facial nerve resection. Severe functional and aesthetic facial defects are the result of a complete sacrifice or injury to isolated branches becoming an uncomfortable distress for patients and a major challenge for reconstructive surgeons.   Case Report: A case of a 54-year-old, systemically healthy male patient with a 4 month complaint of pain and swelling on the right side of the face is presented. The patient reported a rapid increase in the size of the lesion over the past 2 months. Imaging tests and histopathological analysis reported an adenoid cystic carcinoma. A complete parotidectomy was carried out with an intraoperative notice of facial nerve infiltration requiring a second intervention for nerve and defect reconstruction. A free ALT flap with vascularized nerve grafts was the surgical choice. A 6 month follow-up showed partial facial movement recovery and the facial defect mended.   Conclusion:  It is of critical importance to restore function to patients with facial nerve injury.  Vascularized nerve grafts, in many clinical and experimental studies, have shown to result in better nerve regeneration than conventional non-vascularized nerve grafts. Nevertheless, there are factors that may affect the degree, speed and regeneration rate regarding the free fasciocutaneous flap. In complex head and neck defects following a total parotidectomy, the extended free fasciocutaneous ALT (anterior-lateral thigh flap with a vascularized nerve graft is ideally suited for the reconstruction of the injured site.  Donor–site morbidity is low and additional surgical time is minimal

  3. Promising Technique for Facial Nerve Reconstruction in Extended Parotidectomy

    Science.gov (United States)

    Villarreal, Ithzel Maria; Rodríguez-Valiente, Antonio; Castelló, Jose Ramon; Górriz, Carmen; Montero, Oscar Alvarez; García-Berrocal, Jose Ramon

    2015-01-01

    Introduction: Malignant tumors of the parotid gland account scarcely for 5% of all head and neck tumors. Most of these neoplasms have a high tendency for recurrence, local infiltration, perineural extension, and metastasis. Although uncommon, these malignant tumors require complex surgical treatment sometimes involving a total parotidectomy including a complete facial nerve resection. Severe functional and aesthetic facial defects are the result of a complete sacrifice or injury to isolated branches becoming an uncomfortable distress for patients and a major challenge for reconstructive surgeons. Case Report: A case of a 54-year-old, systemically healthy male patient with a 4 month complaint of pain and swelling on the right side of the face is presented. The patient reported a rapid increase in the size of the lesion over the past 2 months. Imaging tests and histopathological analysis reported an adenoid cystic carcinoma. A complete parotidectomy was carried out with an intraoperative notice of facial nerve infiltration requiring a second intervention for nerve and defect reconstruction. A free ALT flap with vascularized nerve grafts was the surgical choice. A 6 month follow-up showed partial facial movement recovery and the facial defect mended. Conclusion: It is of critical importance to restore function to patients with facial nerve injury. Vascularized nerve grafts, in many clinical and experimental studies, have shown to result in better nerve regeneration than conventional non-vascularized nerve grafts. Nevertheless, there are factors that may affect the degree, speed and regeneration rate regarding the free fasciocutaneous flap. In complex head and neck defects following a total parotidectomy, the extended free fasciocutaneous ALT (anterior-lateral thigh) flap with a vascularized nerve graft is ideally suited for the reconstruction of the injured site. Donor–site morbidity is low and additional surgical time is minimal compared with the time of a single

  4. Biomechanical Alignment of Main Wear-Pattern on MOM Total Hip Replacement

    Directory of Open Access Journals (Sweden)

    Paul Burton

    2015-08-01

    Full Text Available In the majority of retrievals, femoral heads and cups are sent for analysis with no designation as to positioning in-vivo. In addition, when patients retain the femoral prosthesis, evidence of neck impingement damage is lost. In this case report we studied head and cup wear-patterns and stripe damage in a novel case that included a large diameter metal-on-metal THA that was retrieved with the head still fused to the stem. This provided anatomical positioning of head wear-pattern and stripe damage as represented by the orientation of the femoral stem in radiographic images. We investigated (1 size, shape and location of head and cup wear-patterns, (2 cup-to-stem impingement damage, and (3 head stripe-wear. The head wear-pattern was elliptical in shape, 40mm diameter with area covering 2200 sq.mm. Its hemispherical ratio was 56% with aspect ratio 1.2 and typical of large-diameter MOM retrievals. Wear-pattern extended from 12° above superior head-margin to approximately 40° inferior to polar axis. Centroidal vector in coronal plane was 13° posterior to polar axis and in transverse plane was 19° superior to polar axis. These vector data corresponded well with biomechanical predictions of resultant load axes in gait studies. Stripe damage was identified on the head, and the cup rim could thereby be aligned to verify neck impingement and also head subluxation mechanisms. Cup wear-pattern was not centrally contained, indicating this patient had experienced repetitive edge-wear during gait. Thinning of the cup rim by 350- 400μm indicated that posterior impingement with repetitive anterior subluxation of the head had created this edge-wear.

  5. Bicycle helmets are highly effective at preventing head injury during head impact: head-form accelerations and injury criteria for helmeted and unhelmeted impacts.

    Science.gov (United States)

    Cripton, Peter A; Dressler, Daniel M; Stuart, Cameron A; Dennison, Christopher R; Richards, Darrin

    2014-09-01

    Cycling is a popular form of recreation and method of commuting with clear health benefits. However, cycling is not without risk. In Canada, cycling injuries are more common than in any other summer sport; and according to the US National Highway and Traffic Safety Administration, 52,000 cyclists were injured in the US in 2010. Head injuries account for approximately two-thirds of hospital admissions and three-quarters of fatal injuries among injured cyclists. In many jurisdictions and across all age levels, helmets have been adopted to mitigate risk of serious head injuries among cyclists and the majority of epidemiological literature suggests that helmets effectively reduce risk of injury. Critics have raised questions over the actual efficacy of helmets by pointing to weaknesses in existing helmet epidemiology including selection bias and lack of appropriate control for the type of impact sustained by the cyclist and the severity of the head impact. These criticisms demonstrate the difficulty in conducting epidemiology studies that will be regarded as definitive and the need for complementary biomechanical studies where confounding factors can be adequately controlled. In the bicycle helmet context, there is a paucity of biomechanical data comparing helmeted to unhelmeted head impacts and, to our knowledge, there is no data of this type available with contemporary helmets. In this research, our objective was to perform biomechanical testing of paired helmeted and unhelmeted head impacts using a validated anthropomorphic test headform and a range of drop heights between 0.5m and 3.0m, while measuring headform acceleration and Head Injury Criterion (HIC). In the 2m (6.3m/s) drops, the middle of our drop height range, the helmet reduced peak accelerations from 824g (unhelmeted) to 181g (helmeted) and HIC was reduced from 9667 (unhelmeted) to 1250 (helmeted). At realistic impact speeds of 5.4m/s (1.5m drop) and 6.3m/s (2.0m drop), bicycle helmets changed the

  6. Bilateral iris, choroid, optic nerve colobomas and retinal detachment ...

    African Journals Online (AJOL)

    Rabah M. Shawky

    2013-12-05

    Dec 5, 2013 ... low posterior hair line, partial left simian crease, and short fingers. MRI brain shows ... The patient has mild mental retardation, now she can walk, dress, and feed ... and acoustic evidence of optic nerve head coloboma. B-scan.

  7. Computational biomechanics of human brain with and without the inclusion of the body under different blast orientation.

    Science.gov (United States)

    Salimi Jazi, Mehdi; Rezaei, Asghar; Azarmi, Fardad; Ziejewski, Mariusz; Karami, Ghodrat

    2016-01-01

    Three different human head models in a free space are exposed to blast waves coming from four different directions. The four head-neck-body models composed of model a, with the neck free in space; model b, with neck fixed at the bottom; and model c, with the neck attached to the body. The results show that the effect of the body can be ignored for the first milliseconds of the head-blast wave interactions. Also one can see that although most biomechanical responses of the brain have similar patterns in all models, the shear stresses are heavily increased after a few milliseconds in model b in which the head motion is obstructed by the fixed-neck boundary conditions. The free-floating head model results are closer to the attached-body model.

  8. Quantifying Head Impact Exposure in Collegiate Women's Soccer.

    Science.gov (United States)

    Press, Jaclyn N; Rowson, Steven

    2017-03-01

    The aim of this study was to quantify head impact exposure for a collegiate women's soccer team over the course of the 2014 season. Observational and prospective study. Virginia Tech women's soccer games and practices. Twenty-six collegiate level women's soccer players with a mean player age of 19 ± 1. Participating players were instrumented with head impact sensors for biomechanical analysis. Video recordings of each event were used to manually verify each impact sustained. Head impact counts by player position and impact situation. The sensors collected data from a total of 17 865 accelerative events, 8999 of which were classified as head impacts. Of these, a total of 1703 impacts were positively identified (19% of total real impacts recorded by sensor), 90% of which were associated with heading the ball. The average number of impacts per player per practice or game was 1.86 ± 1.42. Exposure to head impact varied by player position. Head impact exposure was quantified through 2 different methods, which illustrated the challenges associated with autonomously collecting acceleration data with head impact sensors. Users of head impact data must exercise caution when interpreting on-field head impact sensor data.

  9. Improving the radial nerve neurodynamic test: An observation of tension of the radial, median and ulnar nerves during upper limb positioning.

    Science.gov (United States)

    Manvell, Joshua J; Manvell, Nicole; Snodgrass, Suzanne J; Reid, Susan A

    2015-12-01

    The radial nerve neurodynamic test (ULNT2b), used to implicate symptoms arising from the radial nerve, is proposed to selectively increase strain of the nerve without increasing strain of adjacent tissue, though this has not been established. This study aimed to determine the upper limb position that results in: (1) the greatest tension of the radial nerve and (2) the greatest difference in tension between the radial nerve and the other two major nerves of the upper limb: median and ulnar. Tension (N) of the radial, median and ulnar nerves was measured simultaneously using three buckle force transducers during seven upper limb positions in the axilla of ten embalmed whole body human cadavers (n = 20 limbs). Repeated measures analysis of variance (ANOVA) with Bonferroni post-hoc tests determined differences in tension between nerves and between limb positions. A Composite position consisting of ULNT2b (scapular depression, shoulder internal rotation, elbow extension, forearm pronation, wrist flexion) with the addition of shoulder abduction 40° and extension 25°, wrist ulnar deviation and thumb flexion demonstrated significantly greater tension of the radial nerve than any other tested position (mean tension 11.32N; 95% CI 10.25, 12.29, p < 0.01), including ULNT2b (2.20N; 1.84, 2.57; p < 0.01). Additionally, the Composite position demonstrated the greatest difference in tension between the radial and median (mean difference 4.88N; 95% CI 3.16, 6.61; p < 0.01) and radial and ulnar nerves (9.26N, 7.54, 10.99; p < 0.01). This position constitutes a biomechanically plausible test to detect neuropathic pain related to the radial nerve.

  10. Biomechanical Properties of Bone and Biomechanics of Age - Related Fractures - Review

    Directory of Open Access Journals (Sweden)

    Rezzan Günaydın

    2007-06-01

    Full Text Available From a biomechanical viewpoint, fractures are due to a structural failure of the bone. This failure occurs when the forces applied to the bone exceed its load – bearing capacity. The load – bearing capacity of a bone depends on the geometry (its size, shape and distribution of bone mass, and the material properties of a bone as well as the direction and magnitude of applied load. Bone fragility can be defined by biomechanical parameters such as strength, brittleness and work to failure. Strategies to reduce fracture risk must be based on a sound understanding of the cellular, molecular and biomechanical mechanisms that underlie the increased risk of fractures while aging. In this review biomechanics of bone and the etiology of age – related fractures from a biomechanical viewpoint have been discussed in the view of current literature. (From the World of Osteoporosis 2007;13:44-8

  11. Delayed presentation of traumatic facial nerve (CN VII) paralysis.

    Science.gov (United States)

    Napoli, Anthony M; Panagos, Peter

    2005-11-01

    Facial nerve paralysis (Cranial Nerve VII, CN VII) can be a disfiguring disorder with profound impact upon the patient. The etiology of facial nerve paralysis may be congenital, iatrogenic, or result from neoplasm, infection, trauma, or toxic exposure. In the emergency department, the most common cause of unilateral facial paralysis is Bell's palsy, also known as idiopathic facial paralysis (IFP). We report a case of delayed presentation of unilateral facial nerve paralysis 3 days after sustaining a traumatic head injury. Re-evaluation and imaging of this patient revealed a full facial paralysis and temporal bone fracture extending into the facial canal. Because cranial nerve injuries occur in approximately 5-10% of head-injured patients, a good history and physical examination is important to differentiate IFP from another etiology. Newer generation high-resolution computed tomography (CT) scans are commonly demonstrating these fractures. An understanding of this complication, appropriate patient follow-up, and early involvement of the Otolaryngologist is important in management of these patients. The mechanism as well as the timing of facial nerve paralysis will determine the proper evaluation, consultation, and management for the patient. Patients with total or immediate paralysis as well as those with poorly prognostic audiogram results are good candidates for surgical repair.

  12. A rare Cervical Nerve Root, C2-C3 Schwannoma

    Directory of Open Access Journals (Sweden)

    Nilesh Chordia

    2014-04-01

    Full Text Available Schwannomas, neurilemmomas or neurinomas are benign nerve sheath tumors deriving from Schwann cells that occur in the head and neck region in 25-45% of cases 1 .About 10% of schwannoma that occur in the head and neck region generally originate from the vagus or sympathetic nervous system, those arising from C2 nerve root are extremely rare. 2 Preoperative imaging studies such as magnetic resonance imaging (MRI and computed tomography (CT are used to distinguish its location and origin. The treatment of schwannoma is surgical resection, with several surgical modalities have been introduced to preserve the neurological function. We present a rare case of Cervical nerve (C2-C3 root schwannoma of 70 years old male who presented with lateral neck swelling with no neurological deficit ,swelling which also had intervertebral part was removed successfully through neck incision with no post-operative neurological symptoms

  13. Biological and artificial nerve conduit for repairing peripheral nerve defect

    Institute of Scientific and Technical Information of China (English)

    Xuetao Xie; Changqing Zhang

    2006-01-01

    OBJECTIVE: Recently, with the development of biological and artificial materials, the experimental and clinical studies on application of this new material-type nerve conduit for treatment of peripheral nerve defect have become the hotspot topics for professorial physicians.DATA SOURCES: Using the terms "nerve conduits, peripheral nerve, nerve regeneration and nerve transplantation" in English, we searched Pubmed database, which was published during January 2000 to June 2006, for the literatures related to repairing peripheral nerve defect with various materials. At the same time, we also searched Chinese Technical Scientific Periodical Database at the same time period by inputting" peripheral nerve defect, nerve repair, nerve regeneration and nerve graft" in Chinese.STUDY SELECTION: The materials were firstly selected, and literatures about study on various materials for repairing peripheral nerve defect and their full texts were also searched. Inclusive criteria: nerve conduits related animal experiments and clinical studies. Exclusive criteria: review or repetitive studies.DATA EXTRACTION: Seventy-nine relevant literatures were collected and 30 of them met inclusive criteria and were cited.DATA SYNTHESTS: Peripheral nerve defect, a commonly seen problem in clinic, is difficult to be solved. Autogenous nerve grafting is still the gold standard for repairing peripheral nerve defect, but because of its application limitation and possible complications, people studied nerve conduits to repair nerve defect. Nerve conduits consist of biological and artificial materials.CONCLUSION: There have been numerous reports about animal experimental and clinical studies of various nerve conduits, but nerve conduit, which is more ideal than autogenous nerve grafting, needs further clinical observation and investigation.

  14. Probabilistic Modeling Of Ocular Biomechanics In VIIP: Risk Stratification

    Science.gov (United States)

    Feola, A.; Myers, J. G.; Raykin, J.; Nelson, E. S.; Mulugeta, L.; Samuels, B.; Ethier, C. R.

    2016-01-01

    Visual Impairment and Intracranial Pressure (VIIP) syndrome is a major health concern for long-duration space missions. Currently, it is thought that a cephalad fluid shift in microgravity causes elevated intracranial pressure (ICP) that is transmitted along the optic nerve sheath (ONS). We hypothesize that this in turn leads to alteration and remodeling of connective tissue in the posterior eye which impacts vision. Finite element (FE) analysis is a powerful tool for examining the effects of mechanical loads in complex geometries. Our goal is to build a FE analysis framework to understand the response of the lamina cribrosa and optic nerve head to elevations in ICP in VIIP. To simulate the effects of different pressures on tissues in the posterior eye, we developed a geometric model of the posterior eye and optic nerve sheath and used a Latin hypercubepartial rank correlation coef-ficient (LHSPRCC) approach to assess the influence of uncertainty in our input parameters (i.e. pressures and material properties) on the peak strains within the retina, lamina cribrosa and optic nerve. The LHSPRCC approach was repeated for three relevant ICP ranges, corresponding to upright and supine posture on earth, and microgravity [1]. At each ICP condition we used intraocular pressure (IOP) and mean arterial pressure (MAP) measurements of in-flight astronauts provided by Lifetime Surveillance of Astronaut Health Program, NASA Johnson Space Center. The lamina cribrosa, optic nerve, retinal vessel and retina were modeled as linear-elastic materials, while other tissues were modeled as a Mooney-Rivlin solid (representing ground substance, stiffness parameter c1) with embedded collagen fibers (stiffness parameters c3, c4 and c5). Geometry creationmesh generation was done in Gmsh [2], while FEBio was used for all FE simulations [3]. The LHSPRCC approach resulted in correlation coefficients in the range of 1. To assess the relative influence of the uncertainty in an input parameter on

  15. Head Position and Internally Headed Relative Clauses.

    Science.gov (United States)

    Basilico, David

    1996-01-01

    Examines "Head Movement" in internally headed relative clauses (IHRCs). The article shows that in some cases, head movement to an external position need not take place and demonstrates that this movement of the head to a sentence-internal position results from the quantificational nature of IHRCs and Diesing's mapping hypothesis (1990, 1992). (56…

  16. Biomechanical analysis of rollator walking

    Directory of Open Access Journals (Sweden)

    Nielsen Linda H

    2006-01-01

    Full Text Available Abstract Background The rollator is a very popular walking aid. However, knowledge about how a rollator affects the walking patterns is limited. Thus, the purpose of the study was to investigate the biomechanical effects of walking with and without a rollator on the walking pattern in healthy subjects. Methods The walking pattern during walking with and without rollator was analyzed using a three-dimensional inverse dynamics method. Sagittal joint dynamics and kinematics of the ankle, knee and hip were calculated. In addition, hip joint dynamics and kinematics in the frontal plane were calculated. Seven healthy women participated in the study. Results The hip was more flexed while the knee and ankle joints were less flexed/dorsiflexed during rollator walking. The ROM of the ankle and knee joints was reduced during rollator-walking. Rollator-walking caused a reduction in the knee extensor moment by 50% when compared to normal walking. The ankle plantarflexor and hip abductor moments were smaller when walking with a rollator. In contrast, the angular impulse of the hip extensors was significantly increased during rollator-walking. Conclusion Walking with a rollator unloaded the ankle and especially the knee extensors, increased the hip flexion and thus the contribution of hip extensors to produce movement. Thus, rollator walking did not result in an overall unloading of the muscles and joints of the lower extremities. However, the long-term effect of rollator walking is unknown and further investigation in this field is needed.

  17. Retinal nerve fiber layer thickness is associated with lesion length in acute optic neuritis

    DEFF Research Database (Denmark)

    Kallenbach, K; Simonsen, Helle Juhl; Sander, B;

    2010-01-01

    BACKGROUND: Acute optic neuritis occurs with and without papillitis. The presence of papillitis has previously been thought to imply an anterior location of the neuritis, but imaging studies seeking to test this hypothesis have been inconclusive. METHODS: This prospective observational cohort study...... included 41 patients with unilateral optic neuritis and 19 healthy volunteers. All patients were evaluated and examined within 28 days of onset of symptoms. The peripapillary retinal nerve fiber layer thickness (RNFLT), an objective quantitative measure of optic nerve head edema, was measured by optical...... in the development of optic nerve head edema in optic neuritis....

  18. Effect of clenching with a mouthguard on head acceleration during heading of a soccer ball.

    Science.gov (United States)

    Narimatsu, Keishiro; Takeda, Tomotaka; Nakajima, Kazunori; Konno, Michiyo; Ozawa, Takamitsu; Ishigami, Keiichi

    2015-01-01

    Concussions are acceleration-deceleration injuries that occur when biomechanical forces are transmitted to the cerebral tissues. By limiting acceleration of the head, enhanced cervical muscle activity derived from clenching with a mouthguard (MG) may reduce the incidence or severity of concussions following impact. The purpose of this study was to investigate the effect of voluntary clenching with a proper MG on acceleration of the head during "heading" of a soccer ball. Eleven male high school soccer players (mean age, 16.8 years) participated in the study. Each player was given a customized MG. An automated soccer machine was used to project the ball at the participants at a constant speed. The participants headed the ball under 3 different oral conditions: drill 1, heading freely performed without instruction and without the MG; drill 2, heading performed as the subject was instructed to clench the masseter muscles tightly while not wearing the MG; drill 3, heading performed as the subject was instructed to clench tightly while wearing the MG. Each participant repeated each drill 5 times. Linear acceleration of the head was measured with a 3-axis accelerometer. Activity of the masseter and sternocleidomastoid muscles was measured by wireless electromyography. Weak masseter and sternocleidomastoid muscle activity was observed during drill 1. After the soccer players had been instructed to clench their masseter muscles (drills 2 and 3), statistically significant decreases in head acceleration and increases in masseter and sternocleidomastoid muscle activity were observed (P soccer players to habitually clench while wearing a proper mouthguard to strengthen cervical muscle resistance as a way to mitigate the damage caused by heading.

  19. Biomechanics of the Spine III. The Cranio-Cervical Junction.

    Science.gov (United States)

    Izzo, R; Ambrosanio, G; Cigliano, A; Cascone, D; Gallo, G; Muto, M

    2007-04-30

    By virtue of its unique anatomy and functions the cranial-cervical junction was excluded in previous reviews on the general biomechanics of the spine, being a world apart. The special design of the cranial-cervical (CCJ) junction responds to seemingly opposed necessities being at same time loose enough to allow a great variety of movements and strong enough to preserve the spinal cord and vertebral arteries and to resist the head weight and muscular action. The primary goal of the CCJ is to ensure the maximal mobility of the head for visual and auditory exploration of space. Like a cardan joint the CCJ allows simultaneous independent movements about three axes in order to repeat and extend eye movements under the control of vestibular receptors. Several muscular groups and a number of ligaments control the movements of the CCJ and ensure its stability. Although composed of two seemingly distinct joints the CCJ forms a unique functional complex whose stability is ensured by ligaments and bony restraints often operating on both joint components: the occipitoatlantal and atlantoaxial joints.

  20. Experimental model for civilian ballistic brain injury biomechanics quantification.

    Science.gov (United States)

    Zhang, Jiangyue; Yoganandan, Narayan; Pintar, Frank A; Guan, Yabo; Gennarelli, Thomas A

    2007-01-01

    Biomechanical quantification of projectile penetration using experimental head models can enhance the understanding of civilian ballistic brain injury and advance treatment. Two of the most commonly used handgun projectiles (25-cal, 275 m/s and 9 mm, 395 m/s) were discharged to spherical head models with gelatin and Sylgard simulants. Four ballistic pressure transducers recorded temporal pressure distributions at 308kHz, and temporal cavity dynamics were captured at 20,000 frames/second (fps) using high-speed digital video images. Pressures ranged from 644.6 to -92.8 kPa. Entry pressures in gelatin models were higher than exit pressures, whereas in Sylgard models entry pressures were lower or equivalent to exit pressures. Gelatin responded with brittle-type failure, while Sylgard demonstrated a ductile pattern through formation of micro-bubbles along projectile path. Temporary cavities in Sylgard models were 1.5-2x larger than gelatin models. Pressures in Sylgard models were more sensitive to projectile velocity and diameter increase, indicating Sylgard was more rate sensitive than gelatin. Based on failure patterns and brain tissue rate-sensitive characteristics, Sylgard was found to be an appropriate simulant. Compared with spherical projectile data, full-metal jacket (FMJ) projectiles produced different temporary cavity and pressures, demonstrating shape effects. Models using Sylgard gel and FMJ projectiles are appropriate to enhance understanding and mechanisms of ballistic brain injury.

  1. Linking suckling biomechanics to the development of the palate

    Science.gov (United States)

    Li, Jingtao; Johnson, Chelsey A.; Smith, Andrew A.; Hunter, Daniel J.; Singh, Gurpreet; Brunski, John B.; Helms, Jill A.

    2016-02-01

    Skulls are amongst the most informative documents of evolutionary history but a complex geometry, coupled with composite material properties and complicated biomechanics, have made it particularly challenging to identify mechanical principles guiding the skull’s morphogenesis. Despite this challenge, multiple lines of evidence, for example the relationship between masticatory function and the evolution of jaw shape, nonetheless suggest that mechanobiology plays a major role in skull morphogenesis. To begin to tackle this persistent challenge, cellular, molecular and tissue-level analyses of the developing mouse palate were coupled with finite element modeling to demonstrate that patterns of strain created by mammalian-specific oral behaviors produce complementary patterns of chondrogenic gene expression in an initially homogeneous population of cranial neural crest cells. Neural crest cells change from an osteogenic to a chondrogenic fate, leading to the materialization of cartilaginous growth plate-like structures in the palatal midline. These growth plates contribute to lateral expansion of the head but are transient structures; when the strain patterns associated with suckling dissipate at weaning, the growth plates disappear and the palate ossifies. Thus, mechanical cues such as strain appear to co-regulate cell fate specification and ultimately, help drive large-scale morphogenetic changes in head shape.

  2. Viscoelasticity of repaired sciatic nerve by poly(lactic-co-glycolic acid) tubes

    Institute of Scientific and Technical Information of China (English)

    Chengdong Piao; Peng Li; Guangyao Liu; Kun Yang

    2013-01-01

    Medical-grade synthetic poly(lactic-co-glycolic acid) polymer can be used as a biomaterial for nerve repair because of its good biocompatibility, biodegradability and adjustable degradation rate. The stress relaxation and creep properties of peripheral nerve can be greatly improved by repair with poly(lactic-co-glycolic acid) tubes. Ten sciatic nerve specimens were harvested from fresh corpses within 24 hours of death, and were prepared into sciatic nerve injury models by creating a 10 mm defect in each specimen. Defects were repaired by anastomosis with nerve autografts and poly(lactic-co-glycolic acid) tubes. Stress relaxation and creep testing showed that at 7 200 seconds, the sciatic nerve anastomosed by poly(lactic-co-glycolic acid) tubes exhibited a greater decrease in stress and increase in strain than those anastomosed by nerve autografts. These findings suggest that poly(lactic-co-glycolic acid) exhibits good viscoelasticity to meet the biomechanical require-ments for a biomaterial used to repair sciatic nerve injury.

  3. Viscoelasticity of repaired sciatic nerve by poly(lactic-co-glycolic acid) tubes.

    Science.gov (United States)

    Piao, Chengdong; Li, Peng; Liu, Guangyao; Yang, Kun

    2013-11-25

    Medical-grade synthetic poly(lactic-co-glycolic acid) polymer can be used as a biomaterial for nerve repair because of its good biocompatibility, biodegradability and adjustable degradation rate. The stress relaxation and creep properties of peripheral nerve can be greatly improved by repair with poly(lactic-co-glycolic acid) tubes. Ten sciatic nerve specimens were harvested from fresh corpses within 24 hours of death, and were prepared into sciatic nerve injury models by creating a 10 mm defect in each specimen. Defects were repaired by anastomosis with nerve autografts and poly(lactic-co-glycolic acid) tubes. Stress relaxation and creep testing showed that at 7 200 seconds, the sciatic nerve anastomosed by poly(lactic-co-glycolic acid) tubes exhibited a greater decrease in stress and increase in strain than those anastomosed by nerve autografts. These findings suggest that poly(lactic-co-glycolic acid) exhibits good viscoelasticity to meet the biomechanical require-ments for a biomaterial used to repair sciatic nerve injury.

  4. Human optic nerve head astrocytes culture in vitro:Ⅰ. the primary culture and passage%人眼视神经乳头星形胶质细胞体外培养:Ⅰ.原代培养和传代试验

    Institute of Scientific and Technical Information of China (English)

    戴惟葭; Shelley Culp-Stewwart; Anna Cheng; John Flanagan; C Ross Ethier

    2008-01-01

    AIM: To culture astrocytes from human donor eyes in order to understand the function of astrocytes in remodelling events in the glaucomatous optic nerve head (ONH).METHODS: Primary cultures were prepared by explantation of human ONH tissue in order to get astrocytes. Laminar criborsa (LC) cells were prepared concurrently for comparison. Astrocyte cultures could be separated from LC cells by selecting medium.Similar procedures were used for LC.RESULTS: Primary ceils grew from human optic nerve head explants 4-8 weeks after explantation. Astrocytes had different morphologies and growth characteristics from LC cells. Type 1B astrocyte cells could grow in medium without FBS. Purified cultures were obtained by second passage and could be harvested by third to fifth passage, which were prepared to use for further study, including being characterized by positive glial fibrillary acidic protein (GFAP) and neural cell adhesion molecule (NCAM) staining.CONCLUSION: Precise dissection of fragment is the most important step to get clear explants for primary culture. Economic and rapid method could be useful to select cells by different mediums, which will help us to get more purified cells for further study.%目的:探索人眼视神经乳头星形胶质细胞体外培养的方法,为进一步研究星形胶质细胞在青光眼性视神经病变中的作用打下基础.方法:取材新鲜人眼视神经乳头组织和筛板组织,进行星形胶质细胞和筛板细胞的体外培养与传代试验.结果:组织块培养4~8wk后,原代细胞开始生长,星形胶质细胞在形态学和生长特性上与筛板细胞明显不同, β1型星形胶质细胞可以在无血清的培养液中生长良好,通过无血清培养液选择性培养可以在第二代传代过程中分离出纯化的星形胶质细胞,并可在第三至第四代收获大量细胞以备后续的研究.结论:精细准确的组织解剖分离对于获得纯化细胞至关重要,采用无血清培养液选

  5. Changes in nerve microcirculation following peripheral nerve compression

    Institute of Scientific and Technical Information of China (English)

    Yueming Gao; Changshui Weng; Xinglin Wang

    2013-01-01

    Following peripheral nerve compression, peripheral nerve microcirculation plays important roles in regulating the nerve microenvironment and neurotrophic substances, supplying blood and oxygen and maintaining neural conduction and axonal transport. This paper has retrospectively analyzed the articles published in the past 10 years that addressed the relationship between peripheral nerve compression and changes in intraneural microcirculation. In addition, we describe changes in different peripheral nerves, with the aim of providing help for further studies in peripheral nerve microcirculation and understanding its protective mechanism, and exploring new clinical methods for treating peripheral nerve compression from the perspective of neural microcirculation.

  6. Biomechanics and mechanobiology in functional tissue engineering

    Science.gov (United States)

    Guilak, Farshid; Butler, David L.; Goldstein, Steven A.; Baaijens, Frank P.T.

    2014-01-01

    The field of tissue engineering continues to expand and mature, and several products are now in clinical use, with numerous other preclinical and clinical studies underway. However, specific challenges still remain in the repair or regeneration of tissues that serve a predominantly biomechanical function. Furthermore, it is now clear that mechanobiological interactions between cells and scaffolds can critically influence cell behavior, even in tissues and organs that do not serve an overt biomechanical role. Over the past decade, the field of “functional tissue engineering” has grown as a subfield of tissue engineering to address the challenges and questions on the role of biomechanics and mechanobiology in tissue engineering. Originally posed as a set of principles and guidelines for engineering of load-bearing tissues, functional tissue engineering has grown to encompass several related areas that have proven to have important implications for tissue repair and regeneration. These topics include measurement and modeling of the in vivo biomechanical environment; quantitative analysis of the mechanical properties of native tissues, scaffolds, and repair tissues; development of rationale criteria for the design and assessment of engineered tissues; investigation of the effects biomechanical factors on native and repair tissues, in vivo and in vitro; and development and application of computational models of tissue growth and remodeling. Here we further expand this paradigm and provide examples of the numerous advances in the field over the past decade. Consideration of these principles in the design process will hopefully improve the safety, efficacy, and overall success of engineered tissue replacements. PMID:24818797

  7. SPORT AND EXERCISE BIOMECHANICS (BIOS INSTANT NOTES

    Directory of Open Access Journals (Sweden)

    Paul Grimshaw

    2007-06-01

    Full Text Available DESCRIPTION Instant Notes on Sport and Exercise Biomechanics provides a broad overview of the fundamental concepts in exercise and sport biomechanics. PURPOSE The book aims to provide instant notes on essential information about biomechanics, and is designed to help undergraduate students to grasp the corresponding subjects in physical effort rapidly and easily. AUDIENCE The book provides a useful resource for undergraduate and graduate students as a fundamental reference book. For the researcher and lecturer it would be a starting point to plan and prepare more detailed experimental designs or lecture and/or laboratory classes in the field of exercise and sport biomechanics. It would also be interest to anyone who wonders the concepts like momentum possessed, whole body angular momentum, opposite parallel forces, superman position, parabolic flight path, joint/normal reaction force, etc. FEATURES This textbook is divided into following sections from A to F: kinematics of motion, kinetics of linear motion, kinetics of angular motion, special topics, applications and measurement techniques, respectively. In sub-sections the kinematics of motion are reviewed in detail, outlining the physics of motion. Furthermore, the discussions of mechanical characteristics of motion, the mechanisms of injury, and the analysis of the sport technique provide a source of valuable information for both students and lecturers in appropriate fields. ASSESSMENT This book is an important reading for biomechanics students, teachers and even researchers as well as anyone interested in understanding motion.

  8. [Hypoglossal nerve neuropraxia after shoulder hemiarthroplasty].

    Science.gov (United States)

    Pariente, L; Camarena, P; Koo, M; Sabaté, A; Armengol, J

    2014-05-01

    We report a case of hypoglossal nerve damage after shoulder hemiarthroplasty with the patient in "beach chair" position, performed with general anesthesia with orotracheal intubation, and without complications. An ultrasound-guided interscalene block was previously performed in an alert patient. After the intervention, the patient showed clinical symptomatology compatible with paralysis of the right hypoglossal nerve that completely disappeared after 4 weeks. Mechanisms such as hyperextension of the neck during intubation, endotracheal tube cuff pressure, excessive hyperextension, or head lateralization during surgery have been described as causes of this neurological damage. We discuss the causes, the associated factors and suggest preventive measures. Copyright © 2013 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights reserved.

  9. Malignant Peripheral Nerve Sheath Tumour of the Maxilla

    Directory of Open Access Journals (Sweden)

    Puja Sahai

    2014-01-01

    Full Text Available A 38-year-old man was diagnosed with malignant peripheral nerve sheath tumour of the maxilla. He was treated with total maxillectomy. Histopathological examination of the resected specimen revealed a close resection margin. The tumour was of high grade with an MIB-1 labelling index of almost 60%. At six weeks following the surgery, he developed local tumour relapse. The patient succumbed to the disease at five months from the time of diagnosis. The present report underlines the locally aggressive nature of malignant peripheral nerve sheath tumour of the maxilla which necessitates an early therapeutic intervention. A complete resection with clear margins is the most important prognostic factor for malignant peripheral nerve sheath tumour in the head and neck region. Adjuvant radiotherapy may be considered to improve the local control. Future research may demarcate the role of targeted therapy for patients with malignant peripheral nerve sheath tumour.

  10. Biomechanics and physiology in active manual wheelchair propulsion

    NARCIS (Netherlands)

    van der Woude, L H; Veeger, DirkJan (H. E. J.); Dallmeijer, A J; Janssen, T W; Rozendaal, L A

    2001-01-01

    Manual wheelchair propulsion in daily life and sports is increasingly being studied. Initially, an engineering and physiological perspective was taken. More recently a concomitant biomechanics interest is seen. Themes of biomechanical and physiological studies today are performance enhancing aspects

  11. Biomechanics and physiology in active manual wheelchair propulsion

    NARCIS (Netherlands)

    van der Woude, L H; Veeger, DirkJan (H. E. J.); Dallmeijer, A J; Janssen, T W; Rozendaal, L A

    2001-01-01

    Manual wheelchair propulsion in daily life and sports is increasingly being studied. Initially, an engineering and physiological perspective was taken. More recently a concomitant biomechanics interest is seen. Themes of biomechanical and physiological studies today are performance enhancing aspects

  12. Acute onset of trigeminal neuralgia, facial paresis and dysphagia after mild head injury.

    Science.gov (United States)

    Gkekas, Nikolaos; Primikiris, Panagiotis; Georgakoulias, Nikolaos

    2014-01-01

    The authors report the rare and first documented case of concomitant microvascular decompression of trigeminal, facial and glossopharyngeal nerves for the management of intractable to medical therapy acute onset of trigeminal neuralgia, facial paresis and dysphagia after mild head injury.

  13. 4th International Plant Biomechanics Conference Proceedings (Abstracts)

    Energy Technology Data Exchange (ETDEWEB)

    Frank W. Telewski; Lothar H. Koehler; Frank W. Ewers

    2003-07-20

    The 4th International Plant Biomechanics Conference facilitated an interdisciplinary exchange between scientists, engineers, and educators addressing the major questions encountered in the field of Plant Biomechanics. Subjects covered by the conference include: Evolution; Ecology; Mechanoreception; Cell Walls; Genetic Modification; Applied Biomechanics of Whole Plants, Plant Products, Fibers & Composites; Fluid Dynamics; Wood & Trees; Fracture Mechanics; Xylem Pressure & Water Transport; Modeling; and Introducing Plant Biomechanics in Secondary School Education.

  14. Computational biomechanics for medicine from algorithms to models and applications

    CERN Document Server

    Joldes, Grand; Nielsen, Poul; Doyle, Barry; Miller, Karol

    2017-01-01

    This volume comprises the latest developments in both fundamental science and patient-specific applications, discussing topics such as: cellular mechanics; injury biomechanics; biomechanics of heart and vascular system; medical image analysis; and both patient-specific fluid dynamics and solid mechanics simulations. With contributions from researchers world-wide, the Computational Biomechanics for Medicine series of titles provides an opportunity for specialists in computational biomechanics to present their latest methodologies and advancements.

  15. Combining epidemiology and biomechanics in sports injury prevention research: a new approach for selecting suitable controls.

    Science.gov (United States)

    Finch, Caroline F; Ullah, Shahid; McIntosh, Andrew S

    2011-01-01

    -control selection strategy that reflects the importance of biomechanical considerations, which ensures that controls are selected based on the presence of the same global injury mechanism as the cases. To summarize, the general biomechanical principles that should apply to the selection of controls in future case-control studies are as follows: (i) each control must have been exposed to the same global injury mechanism as the case, (e.g. head impact, fall onto outstretched arm); and (ii) intrinsic (individual) factors (e.g. age, sex, skill level) that might modify the person's response to the relevant biomechanical loads are adjusted when either selecting the controls or are in the analysis phase. The same considerations for control selection apply to other study designs such as matched cohort studies or case-crossover studies.

  16. Proximal Humeral Fractures: A Biomechanical Comparison of Locking Plate Constructs in a Cadaveric 3-Part Fracture Model

    OpenAIRE

    2010-01-01

    The purpose of our study was to biomechanically compare, under cyclic loading conditions, fracture site motion, humeral head collapse, and intra-articular hardware penetration in simulated 3-part osteoporotic proximal humeral fractures stabilized with 1 of 2 locking-plate constructs. We performed fixation on simulated 3-part proximal humeral fractures in 10 pairs of cadaveric osteoporotic humeri with a Hand Innovations S3 Proximal Humerus Plate (S3 plate) or an LCP Proximal Humerus Plate (LCP...

  17. On vision in birds: coordination of head-bobbing and gait stabilises vertical head position in quail

    Science.gov (United States)

    2014-01-01

    Introduction Head-bobbing in birds is a conspicuous behaviour related to vision comprising a hold phase and a thrust phase. The timing of these phases has been shown in many birds, including quail, to be coordinated with footfall during locomotion. We were interested in the biomechanics behind this phenomenon. During terrestrial locomotion in birds, the trunk is subjected to gait-specific vertical oscillations. Without compensation, these vertical oscillations conflict with the demands of vision (i.e., a vertically stable head position). We tested the hypothesis that the coordination between head-bobbing and trunk movement is a means of reconciling the conflicting demands of vision and locomotion which should thus vary according to gait. Results Significant differences in the timing of head-bobbing were found between gaits. The thrust phase was initiated just prior to the double support phase in walking (vaulting) trials, whereas in running (bouncing) trials, thrust started around midstance. Altering the timing of head-trunk-coordination in simulations showed that the timing naturally favoured by birds minimizes the vertical displacement of the head. When using a bouncing gait the timing of head bobbing had a compensatory effect on the fluctuation of the potential energy of the bird’s centre of mass. Conclusion The results are consistent with expectations based on the vertical trunk fluctuations observed in biomechanical models of vaulting and bouncing locomotion. The timing of the head-bobbing behaviour naturally favoured by quail benefits vision during vaulting and bouncing gaits and potentially helps reducing the mechanical cost associated with head bobbing when using a bouncing gait. PMID:24666790

  18. Retinal nerve fiber layer thickness is associated with lesion length in acute optic neuritis

    DEFF Research Database (Denmark)

    Kallenbach, K; Simonsen, Helle Juhl; Sander, B

    2010-01-01

    included 41 patients with unilateral optic neuritis and 19 healthy volunteers. All patients were evaluated and examined within 28 days of onset of symptoms. The peripapillary retinal nerve fiber layer thickness (RNFLT), an objective quantitative measure of optic nerve head edema, was measured by optical...... coherence tomography and the length and location of the inflammatory optic nerve lesion were evaluated using MRI. RESULTS: Ophthalmoscopically, 34% of the patients had papillitis. The retinal nerve fiber layer in affected eyes (mean 123.1 microm) was higher during the acute phase than that of fellow eyes...... (mean 98.1 microm, p eyes (mean 97.1 microm, p

  19. Multiscale modeling in biomechanics and mechanobiology

    CERN Document Server

    Hwang, Wonmuk; Kuhl, Ellen

    2015-01-01

    Presenting a state-of-the-art overview of theoretical and computational models that link characteristic biomechanical phenomena, this book provides guidelines and examples for creating multiscale models in representative systems and organisms. It develops the reader's understanding of and intuition for multiscale phenomena in biomechanics and mechanobiology, and introduces a mathematical framework and computational techniques paramount to creating predictive multiscale models.   Biomechanics involves the study of the interactions of physical forces with biological systems at all scales – including molecular, cellular, tissue and organ scales. The emerging field of mechanobiology focuses on the way that cells produce and respond to mechanical forces – bridging the science of mechanics with the disciplines of genetics and molecular biology. Linking disparate spatial and temporal scales using computational techniques is emerging as a key concept in investigating some of the complex problems underlying these...

  20. Sixth Computational Biomechanics for Medicine Workshop

    CERN Document Server

    Nielsen, Poul MF; Miller, Karol; Computational Biomechanics for Medicine : Deformation and Flow

    2012-01-01

    One of the greatest challenges for mechanical engineers is to extend the success of computational mechanics to fields outside traditional engineering, in particular to biology, biomedical sciences, and medicine. This book is an opportunity for computational biomechanics specialists to present and exchange opinions on the opportunities of applying their techniques to computer-integrated medicine. Computational Biomechanics for Medicine: Deformation and Flow collects the papers from the Sixth Computational Biomechanics for Medicine Workshop held in Toronto in conjunction with the Medical Image Computing and Computer Assisted Intervention conference. The topics covered include: medical image analysis, image-guided surgery, surgical simulation, surgical intervention planning, disease prognosis and diagnostics, injury mechanism analysis, implant and prostheses design, and medical robotics.

  1. Damaged axillary nerve (image)

    Science.gov (United States)

    Conditions associated with axillary nerve dysfunction include fracture of the humerus (upper arm bone), pressure from casts or splints, and improper use of crutches. Other causes include systemic disorders that cause neuritis (inflammation of ...

  2. Diabetes and nerve damage

    Science.gov (United States)

    Diabetic neuropathy; Diabetes - neuropathy; Diabetes - peripheral neuropathy ... In people with diabetes, the body's nerves can be damaged by decreased blood flow and a high blood sugar level. This condition is ...

  3. Sacral nerve stimulation.

    Science.gov (United States)

    Matzel, K E; Stadelmaier, U; Besendörfer, M

    2004-01-01

    The current concept of recruiting residual function of an inadequate pelvic organ by electrostimulation involves stimulation of the sacral spinal nerves at the level of the sacral canal. The rationale for applying SNS to fecal incontinence was based on clinical observations of its effect on bowel habits and anorectal continence function in urologic patients (increased anorectal angulation and anal canal closure pressure) and on anatomic considerations: dissection demonstrated a dual peripheral nerve supply of the striated pelvic floor muscles that govern these functions. Because the sacral spinal nerve site is the most distal common location of this dual nerve supply, stimulating here can elicit both functions. Since the first application of SNS in fecal incontinence in 1994, this technique has been improved, the patient selection process modified, and the spectrum of indications expanded. At present SNS has been applied in more than 1300 patients with fecal incontinence limited.

  4. Diabetic Nerve Problems

    Science.gov (United States)

    ... at the wrong times. This damage is called diabetic neuropathy. Over half of people with diabetes get ... you change positions quickly Your doctor will diagnose diabetic neuropathy with a physical exam and nerve tests. ...

  5. Axillary nerve dysfunction

    Science.gov (United States)

    ... is the nerve that helps control the deltoid muscles of the shoulder and the skin around it. A problem with ... can cause difficulty moving your arm. The deltoid muscle of the shoulder may show signs of muscle atrophy . Tests that ...

  6. Degenerative Nerve Diseases

    Science.gov (United States)

    Degenerative nerve diseases affect many of your body's activities, such as balance, movement, talking, breathing, and heart function. Many of these diseases are genetic. Sometimes the cause is a medical ...

  7. Using biomechanics to improve the surgical technique for internal fixation of intracapsular femoral neck fractures.

    Science.gov (United States)

    Wu, Chi-Chuan

    2010-01-01

    Despite advances in science and technology, the success rate for the treatment of displaced intracapsular femoral neck fractures in high-energy injuries remains disappointing. The blood supply system in the femoral head of humans does not favor recovery from these fractures. Once these fractures occur, osteonecrosis and nonunion rates may be as high as 30%, even if the newest technique is used. There are some surgical techniques used to supplement internal fixation to reestablish the blood supply in the femoral head, but none have been evidently successful. After analysis of related studies, the author concludes that immediate surgical treatment using improved techniques incorporating the principles of biomechanics can improve the success rate of treatment of these fractures. Using these principles, the fracture site can achieve sufficient stability. Consequently, the blood supply in the femoral head and neck can be reestablished earlier and loss of reduction of fragments during treatment can be minimized. Thus, the chance of full recovery from these complicated fractures can be maximized. In this study, the biomechanical characteristics of these fractures and the principles associated with the surgical techniques used for treating them are reviewed and clarified. Finally, a surgical technique which is ideal from the author's viewpoint is presented. The author believes that the recommended surgical technique may become the best method for treating these complicated fractures.

  8. The Effect of Combined Glenoid and Humeral Head Defects on Glenohumeral Translation

    OpenAIRE

    Arciero, Robert A.; Parrino, Anthony; Diaz-Doran, Vilmaris; Obopilwe, Elifho; Cote, Mark P.; Mazzocca, Augustus D.; Provencher, Matthew

    2014-01-01

    Objectives: Bone loss in anterior glenohumeral instability has significant clinical implications and is responsible for surgical failure. Previous work has focused on glenoid and humeral head defects separately. There is no prior biomechanical work evaluating the combined effect of these lesions. The purpose of this study is to determine the effect of the combination of humeral head and glenoid bone loss on glenohumeral joint translation in a bipolar bone loss model with a Bankart lesion and ...

  9. Conjoined lumbosacral nerve roots

    Directory of Open Access Journals (Sweden)

    Atila Yılmaz

    2012-03-01

    Full Text Available Lumbosacral nerve root anomalies are a rare group ofcongenital anatomical anomalies. Various types of anomaliesof the lumbosacral nerve roots have been documentedin the available international literature. Ttheseanomalies may consist of a bifid, conjoined structure, ofa transverse course or of a characteristic anastomizedappearance. Firstly described as an incidental findingduring autopsies or surgical procedures performed forlumbar disk herniations and often asymptomatic, lumbosacralnerve root anomalies have been more frequentlydescribed in the last years due to the advances made inradiological diagnosis.

  10. A Biomechanical Comparison of Two Intramedullary Implants for Subtrochanteric Fracture in Two Healing Stages: A Finite Element Analysis

    Directory of Open Access Journals (Sweden)

    Xinlei Wu

    2015-01-01

    Full Text Available Background. The biomechanical effect of two implants, namely, proximal femoral nail antirotation for Asia (PFNA-II and Expert Asian Femoral Nail (A2FN, for treating subtrochanteric fracture during healing stages, is still unclear. Methods. A 3D finite element model of an intact femur was constructed and validated. The fractured and postoperative models were accordingly produced. The postoperative models were loaded with the peak joint forces during gait for the soft and hard callus stages. The effects of stress distribution on the implants, femoral head and callus, and the deformation of the proximal femur were examined. Results. Both implants showed similar biomechanical effect in two healing stages. As the healing duration increased, the von Mises stress of two implants and the tensile stress of the femoral head decreased, whereas the compressive stress of the femoral head increased. However, the PFNA-II operation resulted in higher stress on the implant, lower stress on the proximal femur, and lower compressive stress and higher tensile stress on the callus than A2FN operation. Conclusions. The A2FN implant may provide a biomechanically superior construct for subtrochanteric fracture healing. However, the upper screw of the A2FN implant may be more likely to be loose in the healing process.

  11. Concussion in professional football: biomechanics of the struck player--part 14.

    Science.gov (United States)

    Viano, David C; Casson, Ira R; Pellman, Elliot J

    2007-08-01

    Impacts causing concussion in professional football were simulated in laboratory tests to determine collision mechanics. This study focuses on the biomechanics of concussion in the struck player. Twenty-five helmet impacts were reconstructed using Hybrid III dummies. Head impact velocity, direction, and helmet kinematics-matched game video. Translational and rotational accelerations were measured in both players' heads; 6-axis upper neck responses were measured in all striking and five struck players. Head kinematics and biomechanics were determined for concussed players. Head displacement, rotation, and neck loads were determined because finite element analysis showed maximum strains occurring in the midbrain after the high impact forces. A model was developed of the helmet impact to study the influence of neck strength and other parameters on head responses. The impact response of the concussed player's head includes peak accelerations of 94 +/- 28 g and 6432 +/- 1813 r/s2, and velocity changes of 7.2 +/- 1.8 m/s and 34.8 +/- 15.2 r/s. Near the end of impact (10 ms), head movement is only 20.2 +/- 6.8 mm and 6.9 +/- 2.5 degrees. After impact, there is rapid head displacement involving a fourfold increase to 87.6 +/- 21.2 mm and 29.9 +/- 9.5 degrees with neck tension and bending at 20 ms. Impacts to the front of the helmet, the source of the majority of National Football League concussions, cause rotation primarily around the z axis (superior-inferior axis) because the force is forward of the neck centerline. This twists the head to the right or left an average of 17.6 +/- 12.7 degrees, causing a moment of 17.7 +/- 3.3 Nm and neck tension of 1704 +/- 432 N at 20 ms. The head injury criterion correlates with concussion risk and is proportional to deltaV(4)/d(1.5) for half-sine acceleration. Stronger necks reduce head acceleration, deltaV, and displacement. Even relatively small reductions in deltaV have a large effect on head injury criterion that may reduce

  12. Analysis of Biomechanical Factors in Bend Running

    Directory of Open Access Journals (Sweden)

    Bing Zhang

    2013-03-01

    Full Text Available Sprint running is the demonstration of comprehensive abilities of technology and tactics, under various conditions. However, whether it is just to allocate the tracks for short-distance athletes from different racetracks has been the hot topic. This study analyzes its forces, differences in different tracks and winding influences, in the aspects of sport biomechanics. The results indicate, many disadvantages exist in inner tracks, middle tracks are the best and outer ones are inferior to middle ones. Thus it provides references for training of short-distance items in biomechanics and psychology, etc.

  13. Anatomy and biomechanics of the craniovertebral junction.

    Science.gov (United States)

    Lopez, Alejandro J; Scheer, Justin K; Leibl, Kayla E; Smith, Zachary A; Dlouhy, Brian J; Dahdaleh, Nader S

    2015-04-01

    The craniovertebral junction (CVJ) has unique anatomical structures that separate it from the subaxial cervical spine. In addition to housing vital neural and vascular structures, the majority of cranial flexion, extension, and axial rotation is accomplished at the CVJ. A complex combination of osseous and ligamentous supports allow for stability despite a large degree of motion. An understanding of anatomy and biomechanics is essential to effectively evaluate and address the various pathological processes that may affect this region. Therefore, the authors present an up-to-date narrative review of CVJ anatomy, normal and pathological biomechanics, and fixation techniques.

  14. Role of Aquaporin 0 in lens biomechanics.

    Science.gov (United States)

    Sindhu Kumari, S; Gupta, Neha; Shiels, Alan; FitzGerald, Paul G; Menon, Anil G; Mathias, Richard T; Varadaraj, Kulandaiappan

    2015-07-10

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5(-/-)), AQP0 KO (heterozygous KO: AQP0(+/-); homozygous KO: AQP0(-/-); all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0(+/-) lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and together they help to confer

  15. Biomechanical Evaluation of Strength and Stiffness of Subtalar Joint Arthrodesis Screw Constructs.

    Science.gov (United States)

    Jastifer, James R; Alrafeek, Saif; Howard, Peter; Gustafson, Peter A; Coughlin, Michael J

    2016-04-01

    Subtalar arthrodesis is a common treatment for end-stage subtalar joint arthritis as well as many other clinical problems. The best method of subtalar arthrodesis fixation is unknown. The purpose of this study was to compare the strength of subtalar arthrodesis fixation methods including a single posterior screw (SP), 2 posterior minimally divergent screws (MD) and a 2 screw highly divergent screw (HD) construct for subtalar arthrodesis. A biomechanical study was performed including the three different screw configurations (SP, MD, HD). These surrogate bone specimens were subjected to applied inversion and eversion torques about the subtalar joint axis on a servo-hydraulic load frame. Torsional stiffness of the construct and the maximum torque for each configuration were measured. Additionally, a cadaver study was performed using 5 fresh-frozen cadaver specimens. The perpendicular distance from the divergent screw guide-wire placement was measured from anatomic structures. The HD screw configuration was found to have the highest torsional stiffness in both inversion and eversion, followed by the MD construct and then the SP construct. Similarly, the HD construct had the highest maximum torque versus the MD and SP constructs. All between-group differences were statistically significant (P < .05). The mean distance from key structures to the divergent screw included the sural nerve (13 mm), peroneus brevis tendon (18 mm), tibialis anterior tendon (8 mm), and tibialis posterior tendon (21 mm). This biomechanical and cadaver study supports the use of 2 screws for fixation of subtalar arthrodesis over a single posterior screw. Additionally, we describe a biomechanically superior and potentially safe, alternative 2-screw divergent construct. This study gives biomechanical support for 2 screw, divergent fixation of subtalar arthrodesis or a single over a single screw or two screw minimally divergent construct. © The Author(s) 2015.

  16. Is HEADS in our heads?

    DEFF Research Database (Denmark)

    Boisen, Kirsten A; Hertz, Pernille Grarup; Blix, Charlotte

    2016-01-01

    BACKGROUND: Outpatient clinic visits are a window of opportunity to address health risk behaviors and promote a healthier lifestyle among young people. The HEADS (Home, Education, Eating, Activities, Drugs [i.e. substance use including tobacco, alcohol, and illegal drugs], Sexuality [including...... care professionals participated. We found only small reported differences between staff and young patients regarding whether home, education, and activity were addressed. However, staff reported twice the rate of addressing smoking, alcohol, illegal drugs, sexuality, and contraception compared to young...... patients. Young patients reported that smoking, alcohol, illegal drugs, sexuality, and contraception were addressed significantly more at adult clinics in comparison to pediatric clinics. After controlling for age, gender and duration of illness, according to young patients, adjusted odds ratios...

  17. Anatomical study of sciatic nerve and common peroneal nerve compression

    Institute of Scientific and Technical Information of China (English)

    Mingzhao Jia; Qing Xia; Jinmin Sun; Qiang Zhou; Weidong Wang

    2008-01-01

    BACKGROUND: Many diseases of the common peroneal nerve are a result of sciatic nerve injury. The present study addresses whether anatomical positioning of the sciatic nerve is responsible for these injuries. OBJECTIVE: To analyze anatomical causes of sciatic nerve and common peroneal nerve injury by studying the relationship between the sciatic nerve and piriformis. DESIGN, TIME AND SETTING: Observe and measure repeatedly. The experiment was conducted in the Department of Anatomy, Tianjin Medical College between January and June 2005. MATERIALS: Fifty-two adult cadavers 33 males and 19 females, with a total of 104 hemispheres, and fixed with formaldehyde, were provided by Tianjin Medical College and Tianjin Medical University. METHODS: A posterior cut was made from the lumbosacral region to the upper leg, fully exposing the piriformis and path of the sciatic nerve. MAIN OUTCOME MEASURES: (1) Anatomical characteristics of the tibial nerve and common peroneal nerve. (2) According to different areas where the sciatic nerve crosses the piriformis, the study was divided into two types--normal and abnormal. Normal is considered to be when the sciatic nerve passes through the infrapiriform foramen. Remaining pathways are considered to be abnormal. (3) Observe the relationship between the suprapiriform foramen, infrapiriform foramen, as well as the superior and inferior space of piriformis. RESULTS: (1) The nerve tract inside the common peroneal nerve is smaller and thinner, with less connective tissue than the tibial nerve. When pathological changes or variations of the piriformis, or over-abduction of the hip joint, occur, injury to the common peroneal nerve often arises due to blockage and compression. (2) A total of 76 hemispheres (73.08%) were normal, 28 were abnormal (26.92%). The piriformis can be injured, and the sciatic nerve can become compressed, when the hip joint undergoes intorsion, extorsion, or abduction. (3) The structures between the infrapiriform and

  18. [Anatomic study on intercostal nerve transfer to suprascapular nerve].

    Science.gov (United States)

    Chu, Bin; Hu, Shaonan; Chen, Liang; Song, Jie

    2012-09-01

    To investigate the feasibility of the 3rd-6th intercostal nerve transfer to the suprascapular nerve for reconstruction of shoulder abduction. Fifteen thoracic walls (30 sides) were collected from cadavers. The 3rd-6th intercostal nerve length which can be dissected between the midaxillary line and midclavicular the transfer distance between the midaxillary line and midpoint of the clavicular bone (prepared point for neurotization) measured. In 30 sides of specimens, the 3rd and 4th intercostal nerves could be obtained between the midaxillary and midclavicular line, the available length of which was significantly greater than the transfer distance (P intercostal nerve and 16 sides of 6th intercostal nerve were covered by the costal cartilage before reaching the midclavicular line. The available length of the 5th intercostal nerve was similar to the transfer distance (P > 0.01), while the available the 6th intercostal nerve was significantly less than transfer distance (P intercostal nerve length and length (2 cm) of suprascapular nerve was significantly greater than the transfer distance (P intercostal nerve transfer to the suprascapular nerve for reconstruction of shoulder abduction. And 6th intercostal nerve, longer dissociated length may be required for direct coaptation or using a graft for nerve repair.

  19. Optimization and Implementation of Long Nerve Allografts

    Science.gov (United States)

    2014-10-01

    nerve tissue requires a graft to restore continuity and promote nerve regeneration and recovery of function. Presently, there is no acceptable nerve ...for nerve regeneration and meaningful recovering of nerve function that, in several cases was better than autografting. Other decellularized allografts... nerve graft, allograft, nerve regeneration , rehabilitation 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME

  20. Multiple Heads of Gastrocnemius with Bipennate Fiber Arrangement- A Clinically Significant Variation

    Science.gov (United States)

    Rodrigues, Vincent; Nayak, Shivananda

    2016-01-01

    It is common to have additional muscles or muscle slips in the extremities. Some of them may compress the nerves and vessels or restrict the movements, while others may enhance the muscular activity. However, a small number of them may go unnoticed. Knowledge of such variant muscles becomes important for plastic surgeons while performing various reconstructive surgeries and for clinicians while managing the pain. A case of multiple heads of gastrocnemius muscle was observed during routine dissection of the right lower limb of about 70-year-old male cadaver. It was observed that the medial head of gastrocnemius was attached to the femur with 3 thick heads and lateral head was arising from the lateral condyle of femur by 3 thick heads. All the heads of the muscles remained separate till they formed tendocalcaneus. Some of these heads showed bipinnate fiber arrangement. All the heads were innervated by the branches of tibial nerve. As the muscle heads passed down from their origin, they entrapped the sural nerve and sural nerve was seen emerging at the beginning of tendocalcaneus. Further, detailed literature and the clinical and surgical importance of the case are discussed. PMID:27656426

  1. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... of the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a ... of page What are some common uses of the procedure? CT scanning of the head is typically ...

  2. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... of the Head? What is CT Scanning of the Head? Computed tomography, more commonly known as a ... of page What are some common uses of the procedure? CT scanning of the head is typically ...

  3. Biomechanics in dermatology: Recent advances and future directions.

    Science.gov (United States)

    Lewinson, Ryan T; Haber, Richard M

    2017-02-01

    Biomechanics is increasingly being recognized as an important research area in dermatology. To highlight only a few examples, biomechanics has contributed to the development of novel topical therapies for aesthetic and medical purposes, enhanced our understanding of the pathogenesis of plantar melanoma, and provided insight into the epidemiology of psoriatic disease. This article summarizes the findings from recent studies to demonstrate the important role that biomechanics may have in dermatologic disease and therapy and places these biomechanical findings in a clinical context for the practicing physician. In addition, areas for future biomechanics research and development in dermatology are discussed.

  4. Jet-Ricci Geometry of Time-Dependent Human Biomechanics

    CERN Document Server

    Ivancevic, Tijana T

    2009-01-01

    We propose the time-dependent generalization of an `ordinary' autonomous human biomechanics, in which total mechanical + biochemical energy is not conserved. We introduce a general framework for time-dependent biomechanics in terms of jet manifolds derived from the extended musculo-skeletal configuration manifold. The corresponding Riemannian geometrical evolution follows the Ricci flow diffusion. In particular, we show that the exponential-like decay of total biomechanical energy (due to exhaustion of biochemical resources) is closely related to the Ricci flow on the biomechanical configuration manifold. Keywords: Time-dependent biomechanics, extended configuration manifold, configuration bundle, jet manifolds, Ricci flow diffusion

  5. Regeneration of Optic Nerve

    Directory of Open Access Journals (Sweden)

    Kwok-Fai So

    2011-05-01

    Full Text Available The optic nerve is part of the central nervous system (CNS and has a structure similar to other CNS tracts. The axons that form the optic nerve originate in the ganglion cell layer of the retina and extend through the optic tract. As a tissue, the optic nerve has the same organization as the white matter of the brain in regard to its glia. There are three types of glial cells: Oligodendrocytes, astrocytes, and microglia. Little structural and functional regeneration of the CNS takes place spontaneously following injury in adult mammals. In contrast, the ability of the mammalian peripheral nervous system (PNS to regenerate axons after injury is well documented. A number of factors are involved in the lack of CNS regeneration, including: (i the response of neuronal cell bodies against the damage; (ii myelin-mediated inhibition by oligodendrocytes; (iii glial scarring, by astrocytes; (iv macrophage infiltration; and (v insufficient trophic factor support. The fundamental difference in the regenerative capacity between CNS and PNS neuronal cell bodies has been the subject of intensive research. In the CNS the target normally conveys a retrograde trophic signal to the cell body. CNS neurons die because of trophic deprivation. Damage to the optic nerve disconnects the neuronal cell body from its target-derived trophic peptides, leading to the death of retinal ganglion cells. Furthermore, the axontomized neurons become less responsive to the peptide trophic signals they do receive. On the other hand, adult PNS neurons are intrinsically responsive to neurotrophic factors and do not lose trophic responsiveness after axotomy. In this talk different strategies to promote optic-nerve regeneration in adult mammals are reviewed. Much work is still needed to resolve many issues. This is a very important area of neuroregeneration and neuroprotection, as currently there is no cure after traumatic optic nerve injury or retinal disease such as glaucoma, which

  6. Optic Nerve Sheath Mechanics and Permeability in VIIP Syndrome

    Science.gov (United States)

    Raykin, Julia; Best, Lauren; Gleason, Rudy; Mulugeta, Lealem; Myers, Jerry; Nelson, Emily; Samuels, Brian C.; Ethier, C. R.

    2014-01-01

    Long-duration space flight carries the risk of developing Visual Impairment and Intracranial Pressure (VIIP) syndrome, a spectrum of ophthalmic changes including posterior globe flattening, choroidal folds, distension of the optic nerve sheath (ONS), optic nerve kinking and potentially permanent degradation of visual function. The slow onset of VIIP, its chronic nature, and certain clinical features strongly suggest that biomechanical factors acting on the ONS play a role in VIIP. Here we measure several relevant ONS properties needed to model VIIP biomechanics. The ONS (meninges) of fresh porcine eyes (n7) was reflected, the nerve proper was truncated near the sclera, and the meninges were repositioned to create a hollow cylinder of meningeal connective tissue attached to the posterior sclera. The distal end was cannulated, sealed, and pressure clamped (mimicking cerebrospinal fluid [CSF] pressure), while the eye was also cannulated for independent control of intraocular pressure (IOP). The meninges were inflated (CSF pressure cycling 7-50 mmHg) while ONS outer diameter was imaged. In another set of experiments (n4), fluid permeation rate across the meninges was recorded by observing the drainage of an elevated fluid reservoir (30 mmHg) connected to the meninges. The ONS showed behavior typical of soft tissues: viscoelasticity, with hysteresis in early preconditioning cycles and repeatable behavior after 4 cycles, and nonlinear stiffening, particularly at CSF pressures 15 mmHg (Figure). Tangent moduli measured from the loading curve were 372 101, 1199 358, and 2050 379 kPa (mean SEM) at CSF pressures of 7, 15 and 30 mmHg, respectively. Flow rate measurements through the intact meninges at 30mmHg gave a permeability of 1.34 0.46 lmincm2mmHg (mean SEM). The ONS is a tough, strain-stiffening connective tissue that is surprisingly permeable. The latter observation suggests that there could be significant CSF drainage through the ONS into the orbit, likely important

  7. Biomechanics of the pelvic floor musculature

    NARCIS (Netherlands)

    Janda, S.

    2006-01-01

    The present thesis was motivated by two main goals. The first research goal of the thesis was to understand the complex biomechanical behaviour of the pelvic floor muscles. The second goal was to study the mechanism of the pelvic organ prolapse (genital prolapse). The pelvic floor in humans is a ve

  8. The Value of Biomechanical Research in Dance.

    Science.gov (United States)

    Ranney, D. A.

    Simple observation of dance movement, while very useful, can lead to misconceptions, about the physical realities of dance movement, that make learning difficult. This gap between reality and understanding can be reduced by the application of biomechanical techniques such as cinematography, electromyography, and force-plate analysis. Biomechanical…

  9. Alteration of biomechanical properties of burned skin.

    Science.gov (United States)

    Held, M; Rahmanian-Schwarz, A; Rothenberger, J; Schiefer, J; Janghorban Esfahani, B; Schaller, H E; Jaminet, P

    2015-06-01

    The prevalence of burns in the general population is high. Despite new research findings, skin burns and its resulting tissue damage are still not entirely understood. In particular, little is known about the depth-dependent alteration of skin biomechanical properties of these wounds. Thirty-six burn wounds with six different depths were generated on the abdomen of six Göttingen minipigs. The alteration of skin biomechanical properties was evaluated objectively after 15 and 360 min using a Cutometer device. Biopsies for histological evaluation were taken and the depth of burn was correlated with biomechanical properties. Firmness of skin (R0), overall elasticity (R8) and calculated elasticity (Ue) demonstrated a continuous decrease with an increasing depth of burn 15 min after wound generation. Gross elasticity (R2), net elasticity (R5) and amount of elasticity of the whole curve (R7), however, showed an increase of values with increasing depth of injury. A further decrease of elasticity was demonstrated 360 min after wound generation. The alteration of skin biomechanical properties is a function of damaged tissue structures. The presented results demonstrate a depth-dependent decrease of principal elastic parameters with an increasing depth of burn and the results indicate progressive tissue damage over the time. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

  10. Biomechanics of Pediatric Manual Wheelchair Mobility

    Science.gov (United States)

    Slavens, Brooke A.; Schnorenberg, Alyssa J.; Aurit, Christine M.; Tarima, Sergey; Vogel, Lawrence C.; Harris, Gerald F.

    2015-01-01

    Currently, there is limited research of the biomechanics of pediatric manual wheelchair mobility. Specifically, the biomechanics of functional tasks and their relationship to joint pain and health is not well understood. To contribute to this knowledge gap, a quantitative rehabilitation approach was applied for characterizing upper extremity biomechanics of manual wheelchair mobility in children and adolescents during propulsion, starting, and stopping tasks. A Vicon motion analysis system captured movement, while a SmartWheel simultaneously collected three-dimensional forces and moments occurring at the handrim. A custom pediatric inverse dynamics model was used to evaluate three-dimensional upper extremity joint motions, forces, and moments of 14 children with spinal cord injury (SCI) during the functional tasks. Additionally, pain and health-related quality of life outcomes were assessed. This research found that joint demands are significantly different amongst functional tasks, with greatest demands placed on the shoulder during the starting task. Propulsion was significantly different from starting and stopping at all joints. We identified multiple stroke patterns used by the children, some of which are not standard in adults. One subject reported average daily pain, which was minimal. Lower than normal physical health and higher than normal mental health was found in this population. It can be concluded that functional tasks should be considered in addition to propulsion for rehabilitation and SCI treatment planning. This research provides wheelchair users and clinicians with a comprehensive, biomechanical, mobility assessment approach for wheelchair prescription, training, and long-term care of children with SCI. PMID:26442251

  11. A Biomechanical Analysis of the Karate Chop.

    Science.gov (United States)

    Cavanagh, Peter R.; Landa, Jean

    Although the sport of karate has been somewhat neglected by scientists, the following two isolated biomechanical studies exist in literature: (1) tracings of a karate chop in two planes were presented, but no data was given concerning the rates of movement of the limb segments, and (2) pre- and postimpact phenomena of five subjects were studied,…

  12. The biomechanical interaction between horse and rider

    NARCIS (Netherlands)

    Cocq, de P.

    2012-01-01

    The forces exerted by a rider on a horse have a direct influence on the mechanical load experienced by the horse and consequently on its motion pattern. The aim of this thesis is to explore the biomechanical interaction between rider, saddle and horse in order to get insight in the loading of the

  13. In vivo biomechanics of cruciate ligament injuries

    NARCIS (Netherlands)

    Van de Velde, S.K.

    2016-01-01

    Measuring biomechanics of the knee with an acceptable degree of accuracy is difficult. When the in vivo knee joint motion is analyzed in all its six degrees-of-freedom without compromising on physiological loading conditions, the task becomes even more challenging. This thesis offers a brief

  14. Biomechanics of Distance Running: A Longitudinal Study

    Science.gov (United States)

    Nelson, Richard C.; Gregor, Robert J.

    1976-01-01

    Training for distance running over a long period produces meaningful changes in the running mechanics of experienced runners, as revealed in this longitudinal study of the biomechanical components of stride length, stride rate, stride time, and support and nonsupport time. (MB)

  15. The biomechanical interaction between horse and rider

    NARCIS (Netherlands)

    Cocq, de P.

    2012-01-01

    The forces exerted by a rider on a horse have a direct influence on the mechanical load experienced by the horse and consequently on its motion pattern. The aim of this thesis is to explore the biomechanical interaction between rider, saddle and horse in order to get insight in the loading of the ho

  16. In vivo biomechanics of cruciate ligament injuries

    NARCIS (Netherlands)

    Van de Velde, S.K.

    2016-01-01

    Measuring biomechanics of the knee with an acceptable degree of accuracy is difficult. When the in vivo knee joint motion is analyzed in all its six degrees-of-freedom without compromising on physiological loading conditions, the task becomes even more challenging. This thesis offers a brief overvie

  17. Biomechanics of Pediatric Manual Wheelchair Mobility.

    Science.gov (United States)

    Slavens, Brooke A; Schnorenberg, Alyssa J; Aurit, Christine M; Tarima, Sergey; Vogel, Lawrence C; Harris, Gerald F

    2015-01-01

    Currently, there is limited research of the biomechanics of pediatric manual wheelchair mobility. Specifically, the biomechanics of functional tasks and their relationship to joint pain and health is not well understood. To contribute to this knowledge gap, a quantitative rehabilitation approach was applied for characterizing upper extremity biomechanics of manual wheelchair mobility in children and adolescents during propulsion, starting, and stopping tasks. A Vicon motion analysis system captured movement, while a SmartWheel simultaneously collected three-dimensional forces and moments occurring at the handrim. A custom pediatric inverse dynamics model was used to evaluate three-dimensional upper extremity joint motions, forces, and moments of 14 children with spinal cord injury (SCI) during the functional tasks. Additionally, pain and health-related quality of life outcomes were assessed. This research found that joint demands are significantly different amongst functional tasks, with greatest demands placed on the shoulder during the starting task. Propulsion was significantly different from starting and stopping at all joints. We identified multiple stroke patterns used by the children, some of which are not standard in adults. One subject reported average daily pain, which was minimal. Lower than normal physical health and higher than normal mental health was found in this population. It can be concluded that functional tasks should be considered in addition to propulsion for rehabilitation and SCI treatment planning. This research provides wheelchair users and clinicians with a comprehensive, biomechanical, mobility assessment approach for wheelchair prescription, training, and long-term care of children with SCI.

  18. Interdisciplinary Vertical Integration: The Future of Biomechanics

    Science.gov (United States)

    Gregor, Robert J.

    2008-01-01

    The field of biomechanics has grown rapidly in the past 30 years in both size and complexity. As a result, the term might mean different things to different people. This article addresses the issues facing the field in the form of challenges biomechanists face in the future. Because the field is so diverse, strength within the different areas of…

  19. Surface driven biomechanical breast image registration

    Science.gov (United States)

    Eiben, Björn; Vavourakis, Vasileios; Hipwell, John H.; Kabus, Sven; Lorenz, Cristian; Buelow, Thomas; Williams, Norman R.; Keshtgar, M.; Hawkes, David J.

    2016-03-01

    Biomechanical modelling enables large deformation simulations of breast tissues under different loading conditions to be performed. Such simulations can be utilised to transform prone Magnetic Resonance (MR) images into a different patient position, such as upright or supine. We present a novel integration of biomechanical modelling with a surface registration algorithm which optimises the unknown material parameters of a biomechanical model and performs a subsequent regularised surface alignment. This allows deformations induced by effects other than gravity, such as those due to contact of the breast and MR coil, to be reversed. Correction displacements are applied to the biomechanical model enabling transformation of the original pre-surgical images to the corresponding target position. The algorithm is evaluated for the prone-to-supine case using prone MR images and the skin outline of supine Computed Tomography (CT) scans for three patients. A mean target registration error (TRE) of 10:9 mm for internal structures is achieved. For the prone-to-upright scenario, an optical 3D surface scan of one patient is used as a registration target and the nipple distances after alignment between the transformed MRI and the surface are 10:1 mm and 6:3 mm respectively.

  20. Expose Mechanical Engineering Students to Biomechanics Topics

    Science.gov (United States)

    Shen, Hui

    2011-01-01

    To adapt the focus of engineering education to emerging new industries and technologies nationwide and in the local area, a biomechanics module has been developed and incorporated into a mechanical engineering technical elective course to expose mechanical engineering students at ONU (Ohio Northern University) to the biomedical engineering topics.…

  1. Head Impact Laboratory (HIL)

    Data.gov (United States)

    Federal Laboratory Consortium — The HIL uses testing devices to evaluate vehicle interior energy attenuating (EA) technologies for mitigating head injuries resulting from head impacts during mine/...

  2. PERFORATION OF INFERIOR ALVEOLAR NERVE BY MAXILLARY ARTERY. LA PERFORACION DEL NERVIO ALVEOLAR INFERIOR POR LA ARTERIA MAXILAR

    OpenAIRE

    Vanishree S Nayak; Ramachandra Bhat K; Prakash Billakanti Babu

    2011-01-01

    Infratemporal fossa is clinically important anatomical area for the delivery of local anesthetic agents in dentistry and maxillofacial surgery. Variations in the anatomy of the inferior alveolar nerve and maxillary artery were studied in infratemporal dissection. During routine dissection of the head in an adult male cadaver an unusual variation in the origin of the inferior alveolar nerve and its relationship with the surrounding structures was observed. The inferior alveolar nerve originate...

  3. Updates on the diagnosis and treatment of intracranial nerve malignant peripheral nerve sheath tumors

    Directory of Open Access Journals (Sweden)

    L'Heureux-Lebeau B

    2013-04-01

    Full Text Available Bénédicte L'Heureux-Lebeau,1 Issam Saliba2 1University of Montreal, 2Department of Otolaryngology Head and Neck Surgery, Montreal University Hospital Center (CHUM, University of Montreal, Montreal, Quebec, Canada Background: Malignant peripheral nerve sheath tumors (MPNSTs are rare entities and MPNSTs of intracranial nerves are even more sporadic. MPNSTs present diagnosis and treatment challenges since there are no defined diagnosis criteria and no established therapeutic strategies. Methods: We reviewed literature for MPNST-related articles. We found 45 relevant studies in which 60 cases were described. Results: We identified 60 cases of intracranial nerve MPNSTs. The age ranged from 3 to 75 years old. Male to female ratio was 1.5:1. The most involved cranial nerves (CNs were CN VIII (60%, CN V (27%, and CN VII (10%. Most of the MPNSTs reported (47% arose sporadically, 40% arose from a schwannoma, 8% arose from a neurofibroma, and 6% arose from an unspecified nerve tumor. Twenty patients had a history of radiation exposure, four patients had neurofibromatosis type 1 (NF1, four patients had neurofibromatosis type 2 (NF2, and NF2 was suspected in two other patients. Twenty-two patients were treated with radiotherapy and presented a higher survival rate. Seventy-two percent of patients died of their disease while 28% of patients survived. One-year survival rate was 33%. Forty-five percent of tumors recurred and 19% of patients had metastases. Conclusion: MPNSTs involving CNs are very rare. Diagnosis is made in regards to the histological and pathological findings. Imaging may help orient the diagnosis. A preexisting knowledge of the clinical situation is more likely to lead to a correct diagnosis. The mainstay of treatment is radical surgical resection with adjuvant radiotherapy. Since these tumors are associated with a poor prognosis, a close follow-up is mandatory. Keywords: malignant peripheral nerve sheath tumor, MPNST, neurofibroma

  4. ECHOGRAPHIC PICTURE OF OPTIC NERVE GLIOMA IN NEUROFIBROMATOSIS TYPE-1

    Directory of Open Access Journals (Sweden)

    Biljana Kuzmanović

    2002-12-01

    Full Text Available Background. Authors want to present echographic picture of orbital part of low-grade pilocytic astrocytoma involving the optic nerve and/or chiasm and optic tract (optic pathway glioma or visual pathway glioma.Methods. 4 children with neurofibromatosis type-1 complicated with optic pathway glioma diagnosed earlier with magnetic resonance were examined by ultrasound. Standardised A-scan technique was used for optic nerve width measurement. The 30° test and B-scan (axial, transverse and longitudinal sections of both eyes and orbits were performed as well.Results. The optic nerve diameter in our cases ranged from 4.48 to 8.5 mm. Two children had the left side optic pathway glioma, one boy had the right side optic pathway glioma and in one tumour was bilateral. The transversal section of the nerve revealed dark oval and in more perpendicular sections round void of the nerve. As the beam is swept towards the orbital apex void becomes more fusiform. The nerve and its sheaths are markedly widened. An abnormal increase in reflectivity and irregularity of the spike’s pattern is exhibited as well. No calcification along the sheaths is noticed. The transverse section of the tumour demonstrated an »inverse doughnut« sign. The outer whiter outline of the widened sheaths surrounds an inner darker circle. The longitudinal section revealed the optic nerve head continuing into the widened optic nerve. The 30° test was negative. The differential diagnosis of meningeoma, optic neuritis and orbital cysticercosis should be considered.Conclusions. Ultrasound as a cheap, safe, easily repeatable imaging method should become a method of choice for screening optic nerve tumours in neurofibromatosis type-1, especially in children, as well as for follow-up after treatment.

  5. Repair of sciatic nerve defects using tissue engineered nerves*

    Institute of Scientific and Technical Information of China (English)

    Caishun Zhang; Gang Lv

    2013-01-01

    In this study, we constructed tissue-engineered nerves with acel ular nerve al ografts in Sprague-Dawley rats, which were prepared using chemical detergents-enzymatic digestion and mechanical methods, in combination with bone marrow mesenchymal stem cel s of Wistar rats cultured in vitro, to repair 15 mm sciatic bone defects in Wistar rats. At postoperative 12 weeks, electrophysiological detection results showed that the conduction velocity of regenerated nerve after repair with tis-sue-engineered nerves was similar to that after autologous nerve grafting, and was higher than that after repair with acel ular nerve al ografts. Immunohistochemical staining revealed that motor endplates with acetylcholinesterase-positive nerve fibers were orderly arranged in the middle and superior parts of the gastrocnemius muscle;regenerated nerve tracts and sprouted branches were connected with motor endplates, as shown by acetylcholinesterase histochemistry combined with silver staining. The wet weight ratio of the tibialis anterior muscle at the affected contralateral hind limb was similar to the sciatic nerve after repair with autologous nerve grafts, and higher than that after repair with acel ular nerve al ografts. The hind limb motor function at the affected side was significantly improved, indicating that acel ular nerve al ografts combined with bone marrow me-senchymal stem cel bridging could promote functional recovery of rats with sciatic nerve defects.

  6. Dog sciatic nerve gap repaired by artificial tissue nerve graft

    Institute of Scientific and Technical Information of China (English)

    GU Xiaosong; ZHANG Peiyun; WANG Xiaodong; DING Fei; PENG Luping; CHENG Hongbing

    2003-01-01

    The feasibility of repairing dog sciatic nerve damage by using a biodegradable artificial tissue nerve graft enriched with neuroregenerating factors is investigated. The artificial nerve graft was implanted to a 30 mm gap of the sciatic nerve damage in 7 dogs. The dogs with the same nerve damage that were repaired by interposition of the autologous nerve or were given no treatment served as control group 1 or 2, respectively. The observations include gross and morphological observations, immune reaction, electrophysiological examination, fluorescence tracing of the neuron formation and the number of the neurons at the experimental sites, etc. Results showed that 6 months after the implantation of the graft, the regenerated nerve repaired the damage of the sciatic nerve without occurrence of rejection and obvious inflammatory reaction in all 7 dogs, and the function of the sciatic nerve recovered with the nerve conduction velocity of (23.91±11.35)m/s. The regenerated neurons and the forming of axon could be observed under an electron microscope. This proves that artificial tissue nerve graft transplantation can bridge the damaged nerve ends and promote the nerve regeneration.

  7. Acellular Nerve Allografts in Peripheral Nerve Regeneration: A Comparative Study

    Science.gov (United States)

    Moore, Amy M.; MacEwan, Matthew; Santosa, Katherine B.; Chenard, Kristofer E.; Ray, Wilson Z.; Hunter, Daniel A.; Mackinnon, Susan E.; Johnson, Philip J.

    2011-01-01

    Background Processed nerve allografts offer a promising alternative to nerve autografts in the surgical management of peripheral nerve injuries where short deficits exist. Methods Three established models of acellular nerve allograft (cold-preserved, detergent-processed, and AxoGen® -processed nerve allografts) were compared to nerve isografts and silicone nerve guidance conduits in a 14 mm rat sciatic nerve defect. Results All acellular nerve grafts were superior to silicone nerve conduits in support of nerve regeneration. Detergent-processed allografts were similar to isografts at 6 weeks post-operatively, while AxoGen®-processed and cold-preserved allografts supported significantly fewer regenerating nerve fibers. Measurement of muscle force confirmed that detergent-processed allografts promoted isograft-equivalent levels of motor recovery 16 weeks post-operatively. All acellular allografts promoted greater amounts of motor recovery compared to silicone conduits. Conclusions These findings provide evidence that differential processing for removal of cellular constituents in preparing acellular nerve allografts affects recovery in vivo. PMID:21660979

  8. Melanocytoma of the optic nerve head - a diagnostic dilemma

    Directory of Open Access Journals (Sweden)

    Zalilawati Mohmad

    2011-08-01

    Full Text Available The clinical features, autofluorescence, Bscan ultrasonography, optical coherence tomography and fluorescein angiography of the lesion were described. Multiple investigation modalities are needed to confirm the benign nature of the lesion. Careful evaluation and follow-up is crucial to avoid misdiagnosis and erroneous management.

  9. Biomechanics and mechanobiology in functional tissue engineering.

    Science.gov (United States)

    Guilak, Farshid; Butler, David L; Goldstein, Steven A; Baaijens, Frank P T

    2014-06-27

    The field of tissue engineering continues to expand and mature, and several products are now in clinical use, with numerous other preclinical and clinical studies underway. However, specific challenges still remain in the repair or regeneration of tissues that serve a predominantly biomechanical function. Furthermore, it is now clear that mechanobiological interactions between cells and scaffolds can critically influence cell behavior, even in tissues and organs that do not serve an overt biomechanical role. Over the past decade, the field of "functional tissue engineering" has grown as a subfield of tissue engineering to address the challenges and questions on the role of biomechanics and mechanobiology in tissue engineering. Originally posed as a set of principles and guidelines for engineering of load-bearing tissues, functional tissue engineering has grown to encompass several related areas that have proven to have important implications for tissue repair and regeneration. These topics include measurement and modeling of the in vivo biomechanical environment; quantitative analysis of the mechanical properties of native tissues, scaffolds, and repair tissues; development of rationale criteria for the design and assessment of engineered tissues; investigation of the effects biomechanical factors on native and repair tissues, in vivo and in vitro; and development and application of computational models of tissue growth and remodeling. Here we further expand this paradigm and provide examples of the numerous advances in the field over the past decade. Consideration of these principles in the design process will hopefully improve the safety, efficacy, and overall success of engineered tissue replacements. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Does intraarticular inflammation predict biomechanical cartilage properties?

    Science.gov (United States)

    Waldstein, Wenzel; Perino, Giorgio; Jawetz, Shari T; Gilbert, Susannah L; Boettner, Friedrich

    2014-07-01

    Intact cartilage in the lateral compartment is an important requirement for medial unicompartmental knee arthroplasty (UKA). Progression of cartilage degeneration in the lateral compartment is a common failure mode of medial UKA. Little is known about factors that influence the mechanical properties of lateral compartment cartilage. The purposes of this study were to answer the following questions: (1) Does the synovial fluid white blood cell count predict the biomechanical properties of macroscopically intact cartilage of the distal lateral femur? (2) Is there a correlation between MRI grading of synovitis and the biomechanical properties of macroscopically intact cartilage? (3) Is there a correlation between the histopathologic assessment of the synovium and the biomechanical properties of macroscopically intact cartilage? The study included 84 patients (100 knees) undergoing primary TKA for varus osteoarthritis between May 2010 and January 2012. All patients underwent preoperative MRI to assess the degree of synovitis. During surgery, the cartilage of the distal lateral femur was assessed macroscopically using the Outerbridge grading scale. In knees with an Outerbridge grade of 0 or 1, osteochondral plugs were harvested from the distal lateral femur for biomechanical and histologic assessment. The synovial fluid was collected to determine the white blood cell count. Synovial tissue was taken for histologic evaluation of the degree of synovitis. The mean aggregate modulus and the mean dynamic modulus were significantly greater in knees with 150 or less white blood cells/mL synovial fluid compared with knees with greater than 150 white blood cells/mL synovial fluid. There was no correlation among MRI synovitis grades, histopathologic synovitis grades, and biomechanical cartilage properties. The study suggests that lateral compartment cartilage in patients with elevated synovial fluid white blood cell counts has a reduced ability to withstand compressive loads

  11. Neuromuscular ultrasound of cranial nerves.

    Science.gov (United States)

    Tawfik, Eman A; Walker, Francis O; Cartwright, Michael S

    2015-04-01

    Ultrasound of cranial nerves is a novel subdomain of neuromuscular ultrasound (NMUS) which may provide additional value in the assessment of cranial nerves in different neuromuscular disorders. Whilst NMUS of peripheral nerves has been studied, NMUS of cranial nerves is considered in its initial stage of research, thus, there is a need to summarize the research results achieved to date. Detailed scanning protocols, which assist in mastery of the techniques, are briefly mentioned in the few reference textbooks available in the field. This review article focuses on ultrasound scanning techniques of the 4 accessible cranial nerves: optic, facial, vagus and spinal accessory nerves. The relevant literatures and potential future applications are discussed.

  12. Heading and head injuries in soccer.

    Science.gov (United States)

    Kirkendall, D T; Jordan, S E; Garrett, W E

    2001-01-01

    In the world of sports, soccer is unique because of the purposeful use of the unprotected head for controlling and advancing the ball. This skill obviously places the player at risk of head injury and the game does carry some risk. Head injury can be a result of contact of the head with another head (or other body parts), ground, goal post, other unknown objects or even the ball. Such impacts can lead to contusions, fractures, eye injuries, concussions or even, in rare cases, death. Coaches, players, parents and physicians are rightly concerned about the risk of head injury in soccer. Current research shows that selected soccer players have some degree of cognitive dysfunction. It is important to determine the reasons behind such deficits. Purposeful heading has been blamed, but a closer look at the studies that focus on heading has revealed methodological concerns that question the validity of blaming purposeful heading of the ball. The player's history and age (did they play when the ball was leather and could absorb significant amounts of water), alcohol intake, drug intake, learning disabilities, concussion definition and control group use/composition are all factors that cloud the ability to blame purposeful heading. What does seem clear is that a player's history of concussive episodes is a more likely explanation for cognitive deficits. While it is likely that the subconcussive impact of purposeful heading is a doubtful factor in the noted deficits, it is unknown whether multiple subconcussive impacts might have some lingering effects. In addition, it is unknown whether the noted deficits have any affect on daily life. Proper instruction in the technique is critical because if the ball contacts an unprepared head (as in accidental head-ball contacts), the potential for serious injury is possible. To further our understanding of the relationship of heading, head injury and cognitive deficits, we need to: learn more about the actual impact of a ball on the

  13. The role of biomechanics in maximising distance and accuracy of golf shots.

    Science.gov (United States)

    Hume, Patria A; Keogh, Justin; Reid, Duncan

    2005-01-01

    Golf biomechanics applies the principles and technique of mechanics to the structure and function of the golfer in an effort to improve golf technique and performance. A common recommendation for technical correction is maintaining a single fixed centre hub of rotation with a two-lever one-hinge moment arm to impart force on the ball. The primary and secondary spinal angles are important for conservation of angular momentum using the kinetic link principle to generate high club-head velocity. When the golfer wants to maximise the distance of their drives, relatively large ground reaction forces (GRF) need to be produced. However, during the backswing, a greater proportion of the GRF will be observed on the back foot, with transfer of the GRF on to the front foot during the downswing/acceleration phase. Rapidly stretching hip, trunk and upper limb muscles during the backswing, maximising the X-factor early in the downswing, and uncocking the wrists when the lead arm is about 30 degrees below the horizontal will take advantage of the summation of force principle. This will help generate large angular velocity of the club head, and ultimately ball displacement. Physical conditioning will help to recruit the muscles in the correct sequence and to optimum effect. To maximise the accuracy of chipping and putting shots, the golfer should produce a lower grip on the club and a slower/shorter backswing. Consistent patterns of shoulder and wrist movements and temporal patterning result in successful chip shots. Qualitative and quantitative methods are used to biomechanically assess golf techniques. Two- and three-dimensional videography, force plate analysis and electromyography techniques have been employed. The common golf biomechanics principles necessary to understand golf technique are stability, Newton's laws of motion (inertia, acceleration, action reaction), lever arms, conservation of angular momentum, projectiles, the kinetic link principle and the stretch

  14. [Peripheral facial nerve palsy].

    Science.gov (United States)

    Pons, Y; Ukkola-Pons, E; Ballivet de Régloix, S; Champagne, C; Raynal, M; Lepage, P; Kossowski, M

    2013-06-01

    Facial palsy can be defined as a decrease in function of the facial nerve, the primary motor nerve of the facial muscles. When the facial palsy is peripheral, it affects both the superior and inferior areas of the face as opposed to central palsies, which affect only the inferior portion. The main cause of peripheral facial palsies is Bell's palsy, which remains a diagnosis of exclusion. The prognosis is good in most cases. In cases with significant cosmetic sequelae, a variety of surgical procedures are available (such as hypoglossal-facial anastomosis, temporalis myoplasty and Tenzel external canthopexy) to rehabilitate facial aesthetics and function.

  15. Role of Aquaporin 0 in lens biomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Sindhu Kumari, S.; Gupta, Neha [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); Shiels, Alan [Washington University School of Medicine, St. Louis, MO (United States); FitzGerald, Paul G. [Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, CA (United States); Menon, Anil G. [University of Cincinnati College of Medicine, Cincinnati, OH (United States); Mathias, Richard T. [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States); Varadaraj, Kulandaiappan, E-mail: kulandaiappan.varadaraj@stonybrook.edu [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States)

    2015-07-10

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5{sup −/−}), AQP0 KO (heterozygous KO: AQP0{sup +/−}; homozygous KO: AQP0{sup −/−}; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0{sup +/−} lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and

  16. Design and biomechanical study of a modified pedicle screw

    Institute of Scientific and Technical Information of China (English)

    LIU Tao; ZHENG Wen-jie; LI Chang-qing; LIU Guo-dong; ZHOU Yue

    2010-01-01

    body into the UHMWPE block, while the polyaxial screw group showed screw body swung up and down the screw head because of loosening of the ball-in-cup mechanism.Conclusions: The modified screw is well-designed and biomechanically improved. And it can provide sufficient stability for segment fixation as monoaxial screws.

  17. Overview of the Cranial Nerves

    Science.gov (United States)

    ... they were damaged. Cranial nerve disorders can affect smell, taste, vision, sensation in the face, facial expression, ... Cranial Nerve Number Name Function Test 1st Olfactory Smell The ability to smell is tested by asking ...

  18. Bilateral eventration of sciatic nerve

    Directory of Open Access Journals (Sweden)

    T Sharma

    2010-12-01

    Full Text Available During routine dissection of a 60 years male cadaver, it was observed that the two divisions of sciatic nerve were separate in the gluteal region on both the sides with the tibial nerve passing below the piriformis and the common peroneal nerve piercing the piriformis muscle. The abnormal passage of the sciatic nerve (SN, the common peroneal nerve (CPN, and the tibial nerve (TN, either through the piriformis or below the superior gemellus may facilitate compression of these nerves. Knowledge of such patterns is also important for surgeons dealing with piriformis syndrome which affects 5-6% of patients referred for the treatment of back and leg pain. A high division may also account for frequent failures reported with the popliteal block. Keywords: eventration, piriformis muscle, piriformis syndrome, sciatic nerve

  19. Three-dimensional adult male head and skull contours.

    Science.gov (United States)

    Lee, Calvin; Loyd, Andre M; Nightingale, Roger; Myers, Barry S; Damon, Andrew; Bass, Cameron R

    2014-01-01

    Traumatic brain injury (TBI) is a major public health issue, affecting millions of people annually. Anthropomorphic test devices (ATDs) and finite element models (FEMs) provide a means of understanding factors leading to TBI, potentially reducing the occurrence. Thus, there is a need to ensure that these tools accurately model humans. For example, the Hybrid III was not based on 3-dimensional human head shape data. The objective of this study is to produce average head and skull contours for an average U.S. male that can be used for ATDs and FEMs. Computed tomography (CT) scans of adult male heads were obtained from a database provided by the University of Virginia Center for Applied Biomechanics. An orthographic viewer was used to extract head and skull contours from the CT scans. Landmarks were measured graphically using HyperMesh (Altair, HyperWorks). To determine the head occipital condyle (OC) centroid, surface meshes of the OCs were made and the centroid of the surfaces was calculated. The Hybrid III contour was obtained using a MicroScribe Digitizer (Solution Technologies, Inc., Oella, MD). Comparisons of the average male and ATD contours were performed using 2 methods: (1) the midsagittal and midcoronal ATD contours relative to the OC centroid were compared to the corresponding 1 SD range of the average male contours; (2) the ATD sagittal contour was translated relative to the average male sagittal contour to minimize the area between the 2 contours. Average male head and skull contours were created. Landmark measurements were made for the dorsum sellae, nasion skin, nasion bone, infraorbital foramen, and external auditory meatus, all relative to the OC centroid. The Hybrid III midsagittal contour was outside the 1 SD range for 15.2 percent of the average male head contour but only by a maximum distance of 1.5 mm, whereas the Hybrid III midcoronal head contour was outside the 1 SD range for 12.2 percent of the average male head contour by a maximum distance

  20. Comparing the Main Anthropometric and Biomechanical Indexes in Male Adult Wushu Athletes in Taolu and Sanda Disciplines

    Directory of Open Access Journals (Sweden)

    azam daneshvar

    2016-06-01

    Full Text Available Objective: The main aim of the study was comparing the main anthropometric and biomechanics indexes in elite male adult Wushu athletes in both Taolu and Sanda disciplines.  Methods: The sample of the present study included 20 elite male Wushu athletes who were checked for 33 anthropometric and 11 biomechanical indexes. The normality of the data was checked by Kolmogorov–Smirnov normality measure. Factor Analysis was run to determine the main indexes and independent samples .T-test was used at a significance level of p<0.05 to compare the means. Results: The results showed that in Taolu group, sitting height, waist to pelvic circumference ratio and body fat percentage were higher. Also, the weight, arm length, leg length, head circumference, arm circumference in contraction, shoulder width, the width of the wrist and body mass index were greater in the Sanda group. There was a meaningful difference between endurance indices, lower limb  muscular strength, semi dynamic balance in posterior-lateral direction, semi dynamic balance in right-anterior direction, semi dynamic balance in posterior-medial direction, semi dynamic balance in posterior-lateral direction (p<0.05.   Conclusion: There is a significant difference in the main anthropometric and biomechanical indicators of Wushu in both Taolu and Sanda disciplines. It appears that balance, endurance – strength of foot in the biomechanical properties are the most important Indicators in Taolu.

  1. High division of sciatic nerve

    Directory of Open Access Journals (Sweden)

    Tripti Shrivastava

    2014-04-01

    Results: In all except two cadavers, the nerve divided at the apex of the popliteal fossa. In two cadavers the sciatic nerve divided bilaterally in the upper part of thigh. Conclusion: The high division presented in this study can make popliteal nerve blocks partially ineffective. The high division of sciatic nerve must always be borne in mind as they have important clinical implications. [Int J Res Med Sci 2014; 2(2.000: 686-688

  2. Biomechanical Factors in the Adaptations of Insect Tibia Cuticle.

    Science.gov (United States)

    Parle, Eoin; Larmon, Hannah; Taylor, David

    2016-01-01

    Insects are among the most diverse groups of animals on Earth. Their cuticle exoskeletons vary greatly in terms of size and shape, and are subjected to different applied forces during daily activities. We investigated the biomechanics of the tibiae of three different insect species: the desert locust (Schistocerca gregaria), American cockroach (Periplaneta americana) and Death's Head cockroach (Blaberus discoidalis). In a previous work, we showed that these tibiae vary not only in geometry (length, radius and thickness) but also in material quality (Young's modulus) and in the applied stress required to cause failure when loaded in bending. In the present work we used kinematic data from the literature to estimate the forces and stresses arising in vivo for various different activities, and thus calculated factors of safety defined as the ratio between the failure stress and the in vivo stress, adjusting the failure stress to a lower value to allow for fatigue failure in the case of frequently repeated activities. Factors of safety were found to vary considerably, being as little as 1.7 for the most strenuous activities, such as jumping or escaping from tight spaces. Our results show that these limbs have evolved to the point where they are close to optimal, and that instantaneous failure during high-stress activities is more critical than long-term fatigue failure. This work contributes to the discussion on how form and material properties have evolved in response to the mechanical functions of the same body part in different insects.

  3. Optic nerve oxygen tension

    DEFF Research Database (Denmark)

    Kiilgaard, Jens Folke; Pedersen, D B; Eysteinsson, T

    2004-01-01

    The authors have previously reported that carbonic anhydrase inhibitors such as acetazolamide and dorzolamide raise optic nerve oxygen tension (ONPO(2)) in pigs. The purpose of the present study was to investigate whether timolol, which belongs to another group of glaucoma drugs called beta...

  4. Optic nerve oxygen tension

    DEFF Research Database (Denmark)

    Kiilgaard, Jens Folke; Pedersen, D B; Eysteinsson, T

    2004-01-01

    The authors have previously reported that carbonic anhydrase inhibitors such as acetazolamide and dorzolamide raise optic nerve oxygen tension (ONPO(2)) in pigs. The purpose of the present study was to investigate whether timolol, which belongs to another group of glaucoma drugs called beta block...

  5. A Review of Instrumented Equipment to Investigate Head Impacts in Sport

    Directory of Open Access Journals (Sweden)

    Declan A. Patton

    2016-01-01

    Full Text Available Contact, collision, and combat sports have more head impacts as compared to noncontact sports; therefore, such sports are uniquely suited to the investigation of head impact biomechanics. Recent advances in technology have enabled the development of instrumented equipment, which can estimate the head impact kinematics of human subjects in vivo. Literature pertaining to head impact measurement devices was reviewed and usage, in terms of validation and field studies, of such devices was discussed. Over the past decade, instrumented equipment has recorded millions of impacts in the laboratory, on the field, in the ring, and on the ice. Instrumented equipment is not without limitations; however, in vivo head impact data is crucial to investigate head injury mechanisms and further the understanding of concussion.

  6. Imaging the ocular motor nerves.

    NARCIS (Netherlands)

    Ferreira, T.; Verbist, B.M.; Buchem, M. van; Osch, T. van; Webb, A.

    2010-01-01

    The ocular motor nerves (OMNs) comprise the oculomotor, trochlear and the abducens nerves. According to their course, they are divided into four or five anatomic segments: intra-axial, cisternal, cavernous and intra-orbital and, for the abducens nerve, an additional interdural segment. Magnetic reso

  7. Progress of peripheral nerve repair

    Institute of Scientific and Technical Information of China (English)

    陈峥嵘

    2002-01-01

    Study on repair of peripheral nerve injury has been proceeding over a long period of time. With the use of microsurgery technique since 1960s,the quality of nerve repair has been greatly improved. In the past 40 years, with the continuous increase of surgical repair methods, more progress has been made on the basic research of peripheral nerve repair.

  8. An Integrated Biomechanical Model for Microgravity-Induced Visual Impairment

    Science.gov (United States)

    Nelson, Emily S.; Best, Lauren M.; Myers, Jerry G.; Mulugeta, Lealem

    2012-01-01

    When gravitational unloading occurs upon entry to space, astronauts experience a major shift in the distribution of their bodily fluids, with a net headward movement. Measurements have shown that intraocular pressure spikes, and there is a strong suspicion that intracranial pressure also rises. Some astronauts in both short- and long-duration spaceflight develop visual acuity changes, which may or may not reverse upon return to earth gravity. To date, of the 36 U.S. astronauts who have participated in long-duration space missions on the International Space Station, 15 crew members have developed minor to severe visual decrements and anatomical changes. These ophthalmic changes include hyperopic shift, optic nerve distension, optic disc edema, globe flattening, choroidal folds, and elevated cerebrospinal fluid pressure. In order to understand the physical mechanisms behind these phenomena, NASA is developing an integrated model that appropriately captures whole-body fluids transport through lumped-parameter models for the cerebrospinal and cardiovascular systems. This data feeds into a finite element model for the ocular globe and retrobulbar subarachnoid space through time-dependent boundary conditions. Although tissue models and finite element representations of the corneo-scleral shell, retina, choroid and optic nerve head have been integrated to study pathological conditions such as glaucoma, the retrobulbar subarachnoid space behind the eye has received much less attention. This presentation will describe the development and scientific foundation of our holistic model.

  9. Nerve growth factor and injured peripheral nerve regeneration

    Institute of Scientific and Technical Information of China (English)

    Endong Shi; Bingchen Wang; Qingshan Sun

    2008-01-01

    Nerve growth factor (NGF) exhibits many biological activities, such as supply of nutrients, neuroprotection, and the generation and rehabilitation of injured nerves. The neuroprotective and neurotrophic qualities of NGF are generally recognized. NGF may enhance axonal regeneration and myelination of peripheral nerves, as well as cooperatively promote functional recovery of injured nerves and limbs. The clinical efficacy of NGF and its therapeutic potentials are reviewed here. This paper also reviews the latest NGF research developments for repairing injured peripheral nerve, thereby providing scientific evidence for the appropriate clinical application of NGF.

  10. [The superior laryngeal nerve and the superior laryngeal artery].

    Science.gov (United States)

    Lang, J; Nachbaur, S; Fischer, K; Vogel, E

    1987-01-01

    Length, diameter and anastomoses of the nervus vagus and its ganglion inferius were measured 44 halved heads. On the average, 8.65 fiber bundles of the vagus nerve leave the retro-olivary area. In the area of the jugular foramen is the near superior ganglion of the 10th cranial nerve. In this area were found 1.48 (mean value) anastomoses with the 9th cranial nerve. 11.34 mm below the margo terminalis sigmoidea branches off the ramus internus of the accessory nerve which has a length of 9.75 mm. Further anastomoses with the 10th cranial nerve were found. The inferior ganglion of the 10th nerve had a length of 25.47 mm and a diameter of 3.46 mm. Five mm below the ganglion the 10th nerve had a width of 2.9 and a thickness of 1.5 mm. The mean length of the superior sympathetic ganglion was 26.6 mm, its width 7.2 and its thickness 3.4 mm. In nearly all specimens anastomoses of the superior sympathetic ganglion with the ansa cervicalis profunda and the inferior ganglion of the 10th cranial nerve were found. The superior laryngeal nerve branches off about 36 mm below the margo terminalis sigmoidea. The width of this nerve was 1.9 mm, its thickness 0.8 mm on the right and 1.0 mm on the left side. The division in the internal and external rami was found about 21 mm below its origin. Between the n. vagus and thyreohyoid membrane the ramus internus had a length of 64 mm, the length of external ramus between the vagal nerve and the inferior pharyngeal constrictor muscle was 89 mm. Its mean length below the thyreopharyngeal part was 10.7 mm, 8.6 branchlets to the cricothyroid muscle were counted. The superior laryngeal artery had its origin in 80% of cases in the superior thyroideal artery, in 6.8% this vessel was a branch of the external carotid artery. Its average outer diameter was 1.23 mm on the right side and 1.39 mm on the left. The length of this vessel between its origin and the thyreohyoid membrane was 34 mm. In 7% on the right side and in 13% on the left, the superior

  11. Biomedical Imaging and Computational Modeling in Biomechanics

    CERN Document Server

    Iacoviello, Daniela

    2013-01-01

    This book collects the state-of-art and new trends in image analysis and biomechanics. It covers a wide field of scientific and cultural topics, ranging from remodeling of bone tissue under the mechanical stimulus up to optimizing the performance of sports equipment, through the patient-specific modeling in orthopedics, microtomography and its application in oral and implant research, computational modeling in the field of hip prostheses, image based model development and analysis of the human knee joint, kinematics of the hip joint, micro-scale analysis of compositional and mechanical properties of dentin, automated techniques for cervical cell image analysis, and iomedical imaging and computational modeling in cardiovascular disease.   The book will be of interest to researchers, Ph.D students, and graduate students with multidisciplinary interests related to image analysis and understanding, medical imaging, biomechanics, simulation and modeling, experimental analysis.

  12. Cervical spondylosis anatomy: pathophysiology and biomechanics.

    Science.gov (United States)

    Shedid, Daniel; Benzel, Edward C

    2007-01-01

    Cervical spondylosis is the most common progressive disorder in the aging cervical spine. It results from the process of degeneration of the intervertebral discs and facet joints of the cervical spine. Biomechanically, the disc and the facets are the connecting structures between the vertebrae for the transmission of external forces. They also facilitate cervical spine mobility. Symptoms related to myelopathy and radiculopathy are caused by the formation of osteophytes, which compromise the diameter of the spinal canal. This compromise may also be partially developmental. The developmental process, together with the degenerative process, may cause mechanical pressure on the spinal cord at one or multiple levels. This pressure may produce direct neurological damage or ischemic changes and, thus, lead to spinal cord disturbances. A thorough understanding of the biomechanics, the pathology, the clinical presentation, the radiological evaluation, as well as the surgical indications of cervical spondylosis, is essential for the management of patients with cervical spondylosis.

  13. Supplementing biomechanical modeling with EMG analysis

    Science.gov (United States)

    Lewandowski, Beth; Jagodnik, Kathleen; Crentsil, Lawton; Humphreys, Bradley; Funk, Justin; Gallo, Christopher; Thompson, William; DeWitt, John; Perusek, Gail

    2016-01-01

    It is well established that astronauts experience musculoskeletal deconditioning when exposed to microgravity environments for long periods of time. Spaceflight exercise is used to counteract these effects, and the Advanced Resistive Exercise Device (ARED) on the International Space Station (ISS) has been effective in minimizing musculoskeletal losses. However, the exercise devices of the new exploration vehicles will have requirements of limited mass, power and volume. Because of these limitations, there is a concern that the exercise devices will not be as effective as ARED in maintaining astronaut performance. Therefore, biomechanical modeling is being performed to provide insight on whether the small Multi-Purpose Crew Vehicle (MPCV) device, which utilizes a single-strap design, will provide sufficient physiological loading to maintain musculoskeletal performance. Electromyography (EMG) data are used to supplement the biomechanical model results and to explore differences in muscle activation patterns during exercises using different loading configurations.

  14. Biological conduits combining bone marrow mesenchymal stem cells and extracellular matrix to treat long-segment sciatic nerve defects

    Directory of Open Access Journals (Sweden)

    Yang Wang

    2015-01-01

    Full Text Available The transplantation of polylactic glycolic acid conduits combining bone marrow mesenchymal stem cells and extracellular matrix gel for the repair of sciatic nerve injury is effective in some respects, but few data comparing the biomechanical factors related to the sciatic nerve are available. In the present study, rabbit models of 10-mm sciatic nerve defects were prepared. The rabbit models were repaired with autologous nerve, a polylactic glycolic acid conduit + bone marrow mesenchymal stem cells, or a polylactic glycolic acid conduit + bone marrow mesenchymal stem cells + extracellular matrix gel. After 24 weeks, mechanical testing was performed to determine the stress relaxation and creep parameters. Following sciatic nerve injury, the magnitudes of the stress decrease and strain increase at 7,200 seconds were largest in the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells + extracellular matrix gel group, followed by the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells group, and then the autologous nerve group. Hematoxylin-eosin staining demonstrated that compared with the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells group and the autologous nerve group, a more complete sciatic nerve regeneration was found, including good myelination, regularly arranged nerve fibers, and a completely degraded and resorbed conduit, in the polylactic glycolic acid conduit + bone marrow mesenchymal stem cells + extracellular matrix gel group. These results indicate that bridging 10-mm sciatic nerve defects with a polylactic glycolic acid conduit + bone marrow mesenchymal stem cells + extracellular matrix gel construct increases the stress relaxation under a constant strain, reducing anastomotic tension. Large elongations under a constant physiological load can limit the anastomotic opening and shift, which is beneficial for the regeneration and functional reconstruction of sciatic nerve. Better

  15. Role of loading on head stability and effective neck stiffness and viscosity.

    Science.gov (United States)

    Simoneau, Martin; Denninger, Marc; Hain, Timothy C

    2008-07-19

    This experiment tests the hypothesis that loading the head would increase head stability. In particular, we hypothesized that an arrangement of the head so that muscle activation is required to counteract a load would significantly increase effective neck stiffness and viscosity, which would be associated with lower peak head angular velocity following abrupt force perturbations applied to the head. Seven young healthy subjects had their head loaded (preload) using a weight/pulley apparatus. Then, the head was pulled either forward or backward by dropping an additional weight onto the preload, causing an impulse of force followed by an increase in load. We recorded the applied force and head angular velocity. Neck viscoelastic properties as a function of loading were estimated by fitting experimental data to a second-order mathematical model of the head biomechanics. Across preloads varying from 2.22 to 8.89 N, peak head angular velocity decreased by 18.2% for the backward and by 19.9% for forward perturbations. As preload increased, simulated effective neck stiffness and viscosity significantly increased leading to lower peak angular velocity. These results demonstrated that loading reduces peak head angular velocity and that change in muscle stiffness and viscosity is a feasible explanation for this effect. We propose that reduction in peak head velocity could be caused by modulation of the strength of the vestibulo-collic reflex.

  16. A Biomechanical Modeling Guided CBCT Estimation Technique.

    Science.gov (United States)

    Zhang, You; Tehrani, Joubin Nasehi; Wang, Jing

    2017-02-01

    Two-dimensional-to-three-dimensional (2D-3D) deformation has emerged as a new technique to estimate cone-beam computed tomography (CBCT) images. The technique is based on deforming a prior high-quality 3D CT/CBCT image to form a new CBCT image, guided by limited-view 2D projections. The accuracy of this intensity-based technique, however, is often limited in low-contrast image regions with subtle intensity differences. The solved deformation vector fields (DVFs) can also be biomechanically unrealistic. To address these problems, we have developed a biomechanical modeling guided CBCT estimation technique (Bio-CBCT-est) by combining 2D-3D deformation with finite element analysis (FEA)-based biomechanical modeling of anatomical structures. Specifically, Bio-CBCT-est first extracts the 2D-3D deformation-generated displacement vectors at the high-contrast anatomical structure boundaries. The extracted surface deformation fields are subsequently used as the boundary conditions to drive structure-based FEA to correct and fine-tune the overall deformation fields, especially those at low-contrast regions within the structure. The resulting FEA-corrected deformation fields are then fed back into 2D-3D deformation to form an iterative loop, combining the benefits of intensity-based deformation and biomechanical modeling for CBCT estimation. Using eleven lung cancer patient cases, the accuracy of the Bio-CBCT-est technique has been compared to that of the 2D-3D deformation technique and the traditional CBCT reconstruction techniques. The accuracy was evaluated in the image domain, and also in the DVF domain through clinician-tracked lung landmarks.

  17. Biomechanics of pediatric manual wheelchair mobility

    Directory of Open Access Journals (Sweden)

    Brooke A. Slavens

    2015-09-01

    Full Text Available Currently, there is limited research of the biomechanics of pediatric manual wheelchair mobility. Specifically, the biomechanics of functional tasks and their relationship to joint pain and health is not well understood. To contribute to this knowledge gap, a quantitative rehabilitation approach was applied for characterizing upper extremity biomechanics of manual wheelchair mobility in children and adolescents during propulsion, starting and stopping tasks. A Vicon motion analysis system captured movement, while a SmartWheel simultaneously collected three-dimensional forces and moments occurring at the hand-rim. A custom pediatric inverse dynamics model was used to evaluate three-dimensional upper extremity joint motions, forces and moments of 14 children with spinal cord injury (SCI during the functional tasks. Additionally, pain and health-related quality of life outcomes were assessed. This research found that joint demands are significantly different amongst functional tasks, with greatest demands placed on the shoulder during the starting task. Propulsion was significantly different from starting and stopping at all joints. We identified multiple stroke patterns used by the children, some of which are not standard in adults. One subject reported average daily pain, which was minimal. Lower than normal physical health and higher than normal mental health was found in this population. It can be concluded that functional tasks should be considered in addition to propulsion for rehabilitation and SCI treatment planning. This research provides wheelchair users and clinicians with a comprehensive, biomechanical, mobility assessment approach for wheelchair prescription, training, and long-term care of children with SCI.

  18. Biomechanical behavior study of dog's small intestines

    Institute of Scientific and Technical Information of China (English)

    陈柏; 周银生; 穆晓枫

    2002-01-01

    The biomechanical behavior of dog's duodenum and jejunum were studied and a formulation of the stress-strain relation is presented in this paper. The results obtained indicated that the exponential coefficient α and the incremental duodenum of the elastic modulus are both larger than those of the jejunum. It means that the duodenum is more deformable than the jejunum. The experimental results of this work provide basal data for kinematics study of a robotic endoscope.

  19. Development of a biomechanical energy harvester

    OpenAIRE

    Donelan J Maxwell; Naing Veronica; Li Qingguo

    2009-01-01

    Abstract Background Biomechanical energy harvesting–generating electricity from people during daily activities–is a promising alternative to batteries for powering increasingly sophisticated portable devices. We recently developed a wearable knee-mounted energy harvesting device that generated electricity during human walking. In this methods-focused paper, we explain the physiological principles that guided our design process and present a detailed description of our device design with an em...

  20. Ergonomic Evaluation of Biomechanical Hand Function

    OpenAIRE

    Lee, Kyung-Sun; Jung, Myung-Chul

    2014-01-01

    The human hand is a complex structure that performs various functions for activities of daily living and occupations. This paper presents a literature review on the methodologies used to evaluate hand functions from a biomechanics standpoint, including anthropometry, kinematics, kinetics, and electromyography (EMG). Anthropometry describes the dimensions and measurements of the hand. Kinematics includes hand movements and the range of motion of finger joints. Kinetics includes hand models for...

  1. The anatomy and biomechanics of running.

    Science.gov (United States)

    Nicola, Terry L; Jewison, David J

    2012-04-01

    To understand the normal series of biomechanical events of running, a comparative assessment to walking is helpful. Closed kinetic chain through the lower extremities, control of the lumbopelvic mechanism, and overall symmetry of movement has been described well enough that deviations from normal movement can now be associated with specific overuse injuries experienced by runners. This information in combination with a history of the runner's errors in their training program will lead to a more comprehensive treatment and prevention plan for related injuries.

  2. Computational Biomechanics Theoretical Background and BiologicalBiomedical Problems

    CERN Document Server

    Tanaka, Masao; Nakamura, Masanori

    2012-01-01

    Rapid developments have taken place in biological/biomedical measurement and imaging technologies as well as in computer analysis and information technologies. The increase in data obtained with such technologies invites the reader into a virtual world that represents realistic biological tissue or organ structures in digital form and allows for simulation and what is called “in silico medicine.” This volume is the third in a textbook series and covers both the basics of continuum mechanics of biosolids and biofluids and the theoretical core of computational methods for continuum mechanics analyses. Several biomechanics problems are provided for better understanding of computational modeling and analysis. Topics include the mechanics of solid and fluid bodies, fundamental characteristics of biosolids and biofluids, computational methods in biomechanics analysis/simulation, practical problems in orthopedic biomechanics, dental biomechanics, ophthalmic biomechanics, cardiovascular biomechanics, hemodynamics...

  3. Morphology and biomechanics of human heart

    Science.gov (United States)

    Chelnokova, Natalia O.; Golyadkina, Anastasiya A.; Kirillova, Irina V.; Polienko, Asel V.; Ivanov, Dmitry V.

    2016-03-01

    Object of study: A study of the biomechanical characteristics of the human heart ventricles was performed. 80 hearts were extracted during autopsy of 80 corpses of adults (40 women and 40 men) aged 31-70 years. The samples were investigated in compliance with the recommendations of the ethics committee. Methods: Tension and compression tests were performed with help of the uniaxial testing machine Instron 5944. Cardiometry was also performed. Results: In this work, techniques for human heart ventricle wall biomechanical properties estimation were developed. Regularities of age and gender variability in deformative and strength properties of the right and left ventricle walls were found. These properties were characterized by a smooth growth of myocardial tissue stiffness and resistivity at a relatively low strain against reduction in their strength and elasticity from 31-40 to 61-70 years. It was found that tissue of the left ventricle at 61-70 years had a lower stretchability and strength compared with tissues of the right ventricle and septum. These data expands understanding of the morphological organization of the heart ventricles, which is very important for the development of personalized medicine. Taking into account individual, age and gender differences of the heart ventricle tissue biomechanical characteristics allows to rationally choosing the type of patching materials during reconstructive operations on heart.

  4. Current Biomechanical Concepts for Rotator Cuff Repair

    Science.gov (United States)

    2013-01-01

    For the past few decades, the repair of rotator cuff tears has evolved significantly with advances in arthroscopy techniques, suture anchors and instrumentation. From the biomechanical perspective, the focus in arthroscopic repair has been on increasing fixation strength and restoration of the footprint contact characteristics to provide early rehabilitation and improve healing. To accomplish these objectives, various repair strategies and construct configurations have been developed for rotator cuff repair with the understanding that many factors contribute to the structural integrity of the repaired construct. These include repaired rotator cuff tendon-footprint motion, increased tendon-footprint contact area and pressure, and tissue quality of tendon and bone. In addition, the healing response may be compromised by intrinsic factors such as decreased vascularity, hypoxia, and fibrocartilaginous changes or aforementioned extrinsic compression factors. Furthermore, it is well documented that torn rotator cuff muscles have a tendency to atrophy and become subject to fatty infiltration which may affect the longevity of the repair. Despite all the aforementioned factors, initial fixation strength is an essential consideration in optimizing rotator cuff repair. Therefore, numerous biomechanical studies have focused on elucidating the strongest devices, knots, and repair configurations to improve contact characteristics for rotator cuff repair. In this review, the biomechanical concepts behind current rotator cuff repair techniques will be reviewed and discussed. PMID:23730471

  5. Biomechanical issues in endovascular device design.

    Science.gov (United States)

    Moore, James E

    2009-02-01

    The biomechanical nature of the arterial system and its major disease states provides a series of challenges to treatment strategies. Endovascular device design objectives have mostly centered on short-term challenges, such as deployability and immediate restoration of reliable flow channels. The resulting design features may be at odds with long-term clinical success. In-stent restenosis, endoleaks, and loss of device structural integrity (e.g., strut fractures) are all manifestations of a lack of compatibility between the host vessel biomechanical environment and the implant design. Initial attempts to adapt device designs for increased compatibility, including drug-eluting and bioabsorbable stents, barely begin to explore the ways in which implant design can be modulated in time to minimize risk of failure. Biomechanical modeling has the potential to provide a virtual vascular environment in which new designs can be tested for their implications on long-term tissue reaction. These models will be based on high quality, highly resolved imaging information, as well as mechanobiology experiments from the cellular to the whole tissue level. These models can then be extended to incorporate biodegradation mechanics, facilitating the next generations of devices whose designs (including drug delivery profiles) change with time to enhance healing. The possibility of initiating changes in device design or drug release according to information on vascular healing (through clinical intervention or automated methods) provides the opportunity for truly individualized dynamic device design optimization.

  6. Delayed-onset bilateral abducens paresis after head trauma

    Directory of Open Access Journals (Sweden)

    Pravin Salunke

    2012-01-01

    Full Text Available Bilateral sixth nerve paresis following closed head injury, though rare, is a known entity. However, delayed-onset post-traumatic bilateral abducens paresis is extremely rare. We present two cases. The first patient had onset of bilateral abducens paresis 2 weeks after closed head injury and the second patient after 3 days. The cause in the former was detected to be chronic subdural hematoma and in the latter is speculated to be edema/ischemia due to injury to soft tissue structures housing these nerves. The delayed onset of bilateral abducens paresis following head injury may vary according to the cause. There may be another mechanism of injury apart from direct trauma. Though rare, it needs to be evaluated and may have a treatable cause like elevated intracranial pressure.

  7. Pathology of the vestibulocochlear nerve

    Energy Technology Data Exchange (ETDEWEB)

    De Foer, Bert [Department of Radiology, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: bert.defoer@GZA.be; Kenis, Christoph [Department of Radiology, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: christophkenis@hotmail.com; Van Melkebeke, Deborah [Department of Neurology, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: Deborah.vanmelkebeke@Ugent.be; Vercruysse, Jean-Philippe [University Department of ENT, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: jphver@yahoo.com; Somers, Thomas [University Department of ENT, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: Thomas.somers@GZA.be; Pouillon, Marc [Department of Radiology, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: marc.pouillon@GZA.be; Offeciers, Erwin [University Department of ENT, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium)], E-mail: Erwin.offeciers@GZA.be; Casselman, Jan W. [Department of Radiology, AZ Sint-Jan AV Hospital, Ruddershove 10, Bruges (Belgium); Consultant Radiologist, Sint-Augustinus Hospital, Oosterveldlaan 24, 2610 Wilrijk (Belgium); Academic Consultent, University of Ghent (Belgium)], E-mail: jan.casselman@azbrugge.be

    2010-05-15

    There is a large scala of pathology affecting the vestibulocochlear nerve. Magnetic resonance imaging is the method of choice for the investigation of pathology of the vestibulocochlear nerve. Congenital pathology mainly consists of agenesis or hypoplasia of the vestibulocochlear nerve. Tumoral pathology affecting the vestibulocochlear nerve is most frequently located in the internal auditory canal or cerebellopontine angle. Schwannoma of the vestibulocochlear nerve is the most frequently found tumoral lesion followed by meningeoma, arachnoid cyst and epidermoid cyst. The most frequently encountered pathologies as well as some more rare entities are discussed in this chapter.

  8. Post-traumatic acute bilateral facial nerve palsy - a management dilemma

    Directory of Open Access Journals (Sweden)

    Kumar Rakesh

    2015-03-01

    Full Text Available Acute bilateral facial nerve paralysis is a rare clinical entity, and its management remains very controversial (operative or conservative. Here we are presenting a case of acute onset bilateral facial nerve palsy following head injury with bilateral temporal bone fracture with clinico-radiographic contrary. Patient was managed conservatively with complete recovery. By this article, authors want to stress on combining clinical examination and radiological findings for decision making of this rare entity and tried to evaluate the management.

  9. Jet-Ricci Geometry of Time-Dependent Human Biomechanics

    OpenAIRE

    Ivancevic, Tijana T.

    2009-01-01

    We propose the time-dependent generalization of an `ordinary' autonomous human biomechanics, in which total mechanical + biochemical energy is not conserved. We introduce a general framework for time-dependent biomechanics in terms of jet manifolds derived from the extended musculo-skeletal configuration manifold. The corresponding Riemannian geometrical evolution follows the Ricci flow diffusion. In particular, we show that the exponential-like decay of total biomechanical energy (due to exh...

  10. An introduction to biomechanics solids and fluids, analysis and design

    CERN Document Server

    Humphrey, Jay D

    2004-01-01

    Designed to meet the needs of undergraduate students, Introduction to Biomechanics takes the fresh approach of combining the viewpoints of both a well-respected teacher and a successful student. With an eye toward practicality without loss of depth of instruction, this book seeks to explain the fundamental concepts of biomechanics. With the accompanying web site providing models, sample problems, review questions and more, Introduction to Biomechanics provides students with the full range of instructional material for this complex and dynamic field.

  11. Determining degree of optic nerve edema from color fundus photography

    Science.gov (United States)

    Agne, Jason; Wang, Jui-Kai; Kardon, Randy H.; Garvin, Mona K.

    2015-03-01

    Swelling of the optic nerve head (ONH) is subjectively assessed by clinicians using the Frisén scale. It is believed that a direct measurement of the ONH volume would serve as a better representation of the swelling. However, a direct measurement requires optic nerve imaging with spectral domain optical coherence tomography (SD-OCT) and 3D segmentation of the resulting images, which is not always available during clinical evaluation. Furthermore, telemedical imaging of the eye at remote locations is more feasible with non-mydriatic fundus cameras which are less costly than OCT imagers. Therefore, there is a critical need to develop a more quantitative analysis of optic nerve swelling on a continuous scale, similar to SD-OCT. Here, we select features from more commonly available 2D fundus images and use them to predict ONH volume. Twenty-six features were extracted from each of 48 color fundus images. The features include attributes of the blood vessels, optic nerve head, and peripapillary retina areas. These features were used in a regression analysis to predict ONH volume, as computed by a segmentation of the SD-OCT image. The results of the regression analysis yielded a mean square error of 2.43 mm3 and a correlation coefficient between computed and predicted volumes of R = 0:771, which suggests that ONH volume may be predicted from fundus features alone.

  12. Progesterone and peripheral nerve regeneration

    Institute of Scientific and Technical Information of China (English)

    Fei Fan; Haichao Li; Yuwei Wang; Yanglin Zheng; Lianjun Jia; Zhihui Wang

    2006-01-01

    OBJECTIVE: To explore the effect of progesterone on peripheral nerve regeneration.DATA SOURCES: An online search of Medline and OVID databases was under taken to identify articles about progesterone and peripheral nerve regeneration published in English between January 1990 and June 2004 by using the keywords of "peripheral nerve, injury, progesterone, regeneration".STUDY SELECTION: The data were primarily screened, those correlated with progesterone and peripheral nerve regeneration were involved, and their original articles were further searched, the repetitive studies or reviews were excluded.DATA EXTRACTION: Totally 59 articles about progesterone and peripheral nerve regeneration were collected, and 26 of them were involved, the other 33 excluded ones were the repetitive studies or reviews.DATA SYNTHESIS: Recent researches found that certain amount of progesterone could be synthetized in peripheral nervous system, and the expression of progesterone receptor could be found in sensory neurons and Schwann cells. After combined with the receptor, endogenous and exogenous progesterone can accelerate the formation of peripheral nerve myelin sheath, also promote the axonal regeneration.CONCLUSION: Progesterone plays a role in protecting neurons, increasing the sensitivity of nerve tissue to nerve growth factor, and accelerating regeneration of nerve in peripheral nerve regeneration, which provides theoretical references for the treatment of demyelinated disease and nerve injury, as well as the prevention of neuroma, especially that the in vivo level of progesterone should be considered for the elderly people accompanied by neuropathy and patients with congenital luteal phase defect, which is of positive significance in guiding the treatment.

  13. Biomechanical characteristics and determinants of instep soccer kick

    National Research Council Canada - National Science Library

    Kellis, Eleftherios; Katis, Athanasios

    2007-01-01

    Good kicking technique is an important aspect of a soccer player. Therefore, understanding the biomechanics of soccer kicking is particularly important for guiding and monitoring the training process...

  14. An Evidence-Based Videotaped Running Biomechanics Analysis.

    Science.gov (United States)

    Souza, Richard B

    2016-02-01

    Running biomechanics play an important role in the development of injuries. Performing a running biomechanics analysis on injured runners can help to develop treatment strategies. This article provides a framework for a systematic video-based running biomechanics analysis plan based on the current evidence on running injuries, using 2-dimensional (2D) video and readily available tools. Fourteen measurements are proposed in this analysis plan from lateral and posterior video. Identifying simple 2D surrogates for 3D biomechanic variables of interest allows for widespread translation of best practices, and have the best opportunity to impact the highly prevalent problem of the injured runner.

  15. Biomechanics of subcellular structures by non-invasive Brillouin microscopy

    Science.gov (United States)

    Antonacci, Giuseppe; Braakman, Sietse

    2016-11-01

    Cellular biomechanics play a pivotal role in the pathophysiology of several diseases. Unfortunately, current methods to measure biomechanical properties are invasive and mostly limited to the surface of a cell. As a result, the mechanical behaviour of subcellular structures and organelles remains poorly characterised. Here, we show three-dimensional biomechanical images of single cells obtained with non-invasive, non-destructive Brillouin microscopy with an unprecedented spatial resolution. Our results quantify the longitudinal elastic modulus of subcellular structures. In particular, we found the nucleoli to be stiffer than both the nuclear envelope (p biomechanics and its role in pathophysiology.

  16. Unilateral sixth nerve palsy.

    Science.gov (United States)

    Sotoodehnia, Mehran; Safaei, Arash; Rasooli, Fatemeh; Bahreini, Maryam

    2017-06-01

    The diagnosis of cerebral venous sinus thrombosis still remains a real challenge. Seizure, unusual headache with sudden onset, unexplained persistently unilateral vascular headache and neurologic deficit-which is difficult to be attributed to a vascular territory are some of the suggestive symptoms. An isolated sixth nerve palsy is discussed as a rare presentation for cerebral venous thrombosis. Following the extensive investigation to rule out other possible diagnoses, magnetic resonance venogram revealed the final etiology of sixth nerve palsy that was ipsilateral left transverse sinus thrombosis; therefore, anticoagulant treatment with low molecular weight heparin was administered. Rapid and accurate diagnosis and treatment cause to achieve excellent outcomes for most patients. Considering different clinical features, risk factors and high index of suspicion are helpful to reach the diagnosis. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. [Biomechanical test study of rat femurs growing under different stress environment].

    Science.gov (United States)

    Liu, Yingxi; Zhao, Wenzhi; Zhang, Jun; Li, Shouju; Li, Jingnian; Sun, Xiaojiang

    2005-06-01

    By creating two kinds of stress environment in the same animal model, we performed a three-point bending test and a compressing test on the rat femurs growing under different stress conditions to characterize the effect of stress on bone mechanical properties. The right hindlimbs were subjected to sciatic nerve resection to become cripple and were used as unloading group; the left hindlimbs bore excess load and made up the overloading group; the normal rats were used as control group. The animals were encouraged to exercise for half an hour everyday in the morning, noon and evening. The experiment observation finished in four weeks. The biomechanical parameters of femur diaphyses were measured. The experiment results showed that stress environment may change several mechanical parameters of rat femurs. This study indicated that bone tissues can adapt to its stress environment by changing its mechanical properties. The experimental model in this article is practical and reliable.

  18. Tissue engineering and peripheral nerve regeneration (III) -- Sciatic nerve regeneration with PDLLA nerve guide

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The biodegradation rate and biocompatibility of poly(d, l -lactide) (PDLLA) in vivo were evaluated. The aim of this study was to establish a nerve guide constructed by the PDLLA with 3-D microenvironment and to repair a 10 mm of sciatic nerve gap in rats. The process of the nerve regeneration was investigated by histological assessment, electrophysiological examination, and determination of wet weight recovery rate of the gastrocnemius muscle. After 3 weeks, the nerve guide had changed from a transparent to an opaque status. The conduit was degraded and absorbed partly and had lost their strength with breakage at the 9th week of postoperation. At the conclusion of 12 weeks, proximal and distal end of nerves were anastomosed by nerve regeneration and the conduit vanished completely. The results suggest that PDLLA conduits may serve for peripheral nerve regeneration and PDLLA is a sort of hopeful candidate for tissue engineering.

  19. Optic nerve hypoplasia

    Directory of Open Access Journals (Sweden)

    Savleen Kaur

    2013-01-01

    Full Text Available Optic nerve hypoplasia (ONH is a congenital anomaly of the optic disc that might result in moderate to severe vision loss in children. With a vast number of cases now being reported, the rarity of ONH is obviously now refuted. The major aspects of ophthalmic evaluation of an infant with possible ONH are visual assessment, fundus examination, and visual electrophysiology. Characteristically, the disc is small, there is a peripapillary double-ring sign, vascular tortuosity, and thinning of the nerve fiber layer. A patient with ONH should be assessed for presence of neurologic, radiologic, and endocrine associations. There may be maternal associations like premature births, fetal alcohol syndrome, maternal diabetes. Systemic associations in the child include endocrine abnormalities, developmental delay, cerebral palsy, and seizures. Besides the hypoplastic optic nerve and chiasm, neuroimaging shows abnormalities in ventricles or white- or gray-matter development, septo-optic dysplasia, hydrocephalus, and corpus callosum abnormalities. There is a greater incidence of clinical neurologic abnormalities in patients with bilateral ONH (65% than patients with unilateral ONH. We present a review on the available literature on the same to urge caution in our clinical practice when dealing with patients with ONH. Fundus photography, ocular coherence tomography, visual field testing, color vision evaluation, neuroimaging, endocrinology consultation with or without genetic testing are helpful in the diagnosis and management of ONH. (Method of search: MEDLINE, PUBMED.

  20. Cranial nerves in the Australian lungfish, Neoceratodus forsteri, and in fossil relatives (Osteichthyes: Dipnoi).

    Science.gov (United States)

    Kemp, A

    2017-02-01

    Three systems, two sensory and one protective, are present in the skin of the living Australian lungfish, Neoceratodus forsteri, and in fossil lungfish, and the arrangement and innervation of the sense organs is peculiar to lungfish. Peripheral branches of nerves that innervate the sense organs are slender and unprotected, and form before any skeletal structures appear. When the olfactory capsule develops, it traps some of the anterior branches of cranial nerve V, which emerged from the chondrocranium from the lateral sphenotic foramen. Cranial nerve I innervates the olfactory organ enclosed within the olfactory capsule and cranial nerve II innervates the eye. Cranial nerve V innervates the sense organs of the snout and upper lip, and, in conjunction with nerve IX and X, the sense organs of the posterior and lateral head. Cranial nerve VII is primarily a motor nerve, and a single branch innervates sense organs in the mandible. There are no connections between nerves V and VII, although both emerge from the brain close to each other. The third associated system consists of lymphatic vessels covered by an extracellular matrix of collagen, mineralised as tubules in fossils. Innervation of the sensory organs is separate from the lymphatic system and from the tubule system of fossil lungfish.

  1. Intraosseous malignant peripheral nerve sheath tumor of maxilla: A case report with review of the literature

    Directory of Open Access Journals (Sweden)

    Sandhya Tamgadge

    2014-01-01

    Full Text Available Malignant peripheral nerve sheath tumor (MPNST, the principle malignancy of peripheral nerve origin, though rare in the general population, occurs with excessive frequency among patients with neurofibromatosis. This tumor always arises in soft-tissues, usually found in the lower extremities and only 10-12% of all lesions occur in the head and neck region, which makes it a rare entity. The primary intraosseous MPNST is rare and has been reported most frequently in the mandible. This article discusses a case report of MPNST of the left maxilla without a history of benign nerve tissue tumor and the diagnostic difficulties associated with MPNST.

  2. Intraoral Neurinoma of the Lingual Nerve: An Uncommon Tumor in Floor of the Mouth

    Directory of Open Access Journals (Sweden)

    Santhosh Kumar kuppusamy

    2014-01-01

    Full Text Available Neurinoma or schwannoma is an uncommon benign tumor that arises primarily from the nerve sheath of Schwann cells. About 25% has been reported in head and neck region extracranially, but only 1% in the intraoral origin. Intraorally, the tongue is the most common site followed by the palate, floor of the mouth, lips and buccal mucosa. In review of literature, intraoral schwannoma of the lingual nerve origin has not been reported frequently. So, we present a case of intraoral neurinoma of the lingual nerve.

  3. Comparative biomechanical study of reversed less invasive stabilization system and proximal femoral nail antirotation for unstable intertrochanteric fractures

    Institute of Scientific and Technical Information of China (English)

    Chen Ying; Liu Shouyao; Lin Peng; Wang Yunting; Wang Jinhui; Tao Jianfeng; Cai Rongrong

    2014-01-01

    Objective Unstable intertrochanteric fractures (ITFs) are mostly treated by proximal femoral nail antirotation (PFNA),Inter-Tan,Asian Hip,and other new internal fixation devices.But for complex unstable fractures,such as crushed lateral wall of the greater trochanter,the loss of fixation point on lateral wall slightly reduces the fixing effect.This study aimed to compare the biomechanical strengths between reversed less invasive stabilization system (LISS) and PFNA for treatment of unstable ITFs.Methods Forty synthetic femurs were used to simulate unstable ITFs in vitro and were fixed using the reversed LISS or PFNA.These fractures were divided into two groups depending on whether the lateral wall of the greater trochanter is intact or not (AO classification:31-A2.3 and 31-A3.3,respectively).The load-displacement of femur,stiffness,ultimate load,and cyclic fatigue resistance were detected using an incremental load test and a dynamic fatigue test through an MTS 858 test system.Results For both 31-A2.3 and 31-A3.3,the vertical sinking displacement (VSD) of the femoral head under 500 N load was insignificantly smaller after treatment with reversed LISS than with PFNA,and when the displacement was 5 mm,the femoral head bore insignificantly greater load.The fixation with reversed LISS resulted in greater axial stiffness of the femur but smaller ultimate load.During the same cycle in the dynamic fatigue test,the VSD was insignificantly smaller with the fixation of reversed LISS.Conclusion Reversed LISS and PFNA have similar biomechanical strength for unstable ITFs.This conclusion should be supported by additional large-size research on basic biomechanics and clinical application.This is the first comparative biomechanical study comparing reversed LISS and PFNA for unstable ITFs.

  4. Computed Tomography (CT) -- Head

    Medline Plus

    Full Text Available ... limitations of CT Scanning of the Head? What is CT Scanning of the Head? Computed tomography, more ... the body being studied. top of page How is the procedure performed? The technologist begins by positioning ...

  5. Validation of a wireless head acceleration measurement system for use in soccer play.

    Science.gov (United States)

    Hanlon, Erin; Bir, Cynthia

    2010-11-01

    Soccer heading has been studied previously with conflicting results. One major issue is the lack of knowledge regarding what actually occurs biomechanically during soccer heading impacts. The purpose of the current study is to validate a wireless head acceleration measurement system, head impact telemetry system (HITS) that can be used to collect head accelerations during soccer play. The HIT system was fitted to a Hybrid III (HIII) head form that was instrumented with a 3-2-2-2 accelerometer setup. Fifteen impact conditions were tested to simulate impacts commonly experienced during soccer play. Linear and angular acceleration were calculated for both systems and compared. Root mean square (RMS) error and cross correlations were also calculated and compared for both systems. Cross correlation values were very strong with r = .95 ± 0.02 for ball to head forehead impacts and r = .96 ± 0.02 for head to head forehead impacts. The systems showed a strong relationship when comparing RMS error, linear head acceleration, angular head acceleration, and the cross correlation values.

  6. The NerveSeeker: a system for automated nerve localization.

    Science.gov (United States)

    Raymond, S A; Abrams, S B; Raemer, D B; Philip, J H; Strichartz, G R

    1992-01-01

    The NerveSeeker is a new instrument for locating peripheral nerves. Like existing nerve stimulators, it is based on injecting current through the needle used for drug injection. However, the NerveSeeker was designed to automatically adjust the amplitude of the stimulating current pulses. It does this by feedback control to hold the level of response constant at a small but reliably detectable fraction of a maximal neural response. We report experimental tests of the NerveSeeker using an excised frog nerve in a transparent chamber, where we could observe the needle approach. A control voltage proportional to the stimulus magnitude was used to indicate the proximity of the needle tip to the nerve. The proximity was validated by direct measurement of the distance from the tip of the needle to the nerve. Parameters governing the performance of the NerveSeeker in tracking needle movement were analyzed. The following combined strategy was found effective: As the needle approached the nerve, the stimulus was reduced in proportion to the amplitude of the recorded response; as the needle moved away, the stimulus magnitude was incremented by a constant amount (enough to increase the neural response by approximately 1% of its maximum amplitude) after each stimulus that failed to elicit a neural response exceeding the criterion value. Stimulation throughout simulated penetrations was at a frequency of 10 Hz or higher to give more immediate guidance during insertion. Optimal settings for each control parameter were determined, reflecting both engineering and physiologic tradeoffs. With these settings, the device proved successful in localizing nerves, closely tracking needle movements at velocities as high as 2 mm/second. These experimental results suggest that clinical tests of the NerveSeeker would be appropriate.

  7. [Electrical nerve stimulation for plexus and nerve blocks].

    Science.gov (United States)

    Birnbaum, J; Klotz, E; Bogusch, G; Volk, T

    2007-11-01

    Despite the increasing use of ultrasound, electrical nerve stimulation is commonly used as the standard for both plexus and peripheral nerve blocks. Several recent randomized trials have contributed to a better understanding of physiological and clinical correlations. Traditionally used currents and impulse widths are better defined in relation to the distance between needle tip and nerves. Commercially available devices enable transcutaneous nerve stimulation and provide new opportunities for the detection of puncture sites and for training. The electrically ideal position of the needle usually is defined by motor responses which can not be interpreted without profound anatomical knowledge. For instance, interscalene blocks can be successful even after motor responses of deltoid or pectoral muscles. Infraclavicular blocks should be aimed at stimulation of the posterior fascicle (extension). In contrast to multiple single nerve blocks, axillary single-shot blocks more commonly result in incomplete anaesthesia. Blockade of the femoral nerve can be performed without any nerve stimulation if the fascia iliaca block is used. Independently of the various approaches to the sciatic nerve, inversion and plantar flexion are the best options for single-shot blocks. Further clinical trials are needed to define the advantages of stimulating catheters in continuous nerve blocks.

  8. Acetabular roof arc angles and anatomic biomechanical superior acetabular weight bearing area

    Directory of Open Access Journals (Sweden)

    Thossart Harnroongroj

    2014-01-01

    Full Text Available Background: Acetabular fracture involves whether superior articular weight bearing area and stability of the hip are assessed by acetabular roof arc angles comprising medial, anterior and posterior. Many previous studies, based on clinical, biomechanics and anatomic superior articular surface of acetabulum showed different degrees of the angles. Anatomic biomechanical superior acetabular weight bearing area (ABSAWBA of the femoral head can be identified as radiographic subchondral bone density at superior acetabular dome. The fracture passes through ABSAWBA creating traumatic hip arthritis. Therefore, acetabular roof arc angles of ABSAWBA were studied in order to find out that the most appropriate degrees of recommended acetabular roof arc angles in the previous studies had no ABSAWBA involvement. Materials and Methods: ABSAWBA of femoral head was identified 68 acetabular fractures and 13 isolated pelvic fractures without unstable pelvic ring injury were enrolled. Acetabular roof arc angle was measured on anteroposterior, obturator and iliac oblique view radiographs of normal contralateral acetabulum using programmatic automation controller digital system and measurement tools. Results: Average medial, anterior and posterior acetabular roof arc angles of the ABSAWBA of 94 normal acetabulum were 39.09 (7.41, 42.49 (8.15 and 55.26 (10.08 degrees, respectively. Conclusions: Less than 39°, 42° and 55° of medial, anterior and posterior acetabular roof arc angles involve ABSAWBA of the femoral head. Application of the study results showed that 45°, 45° and 62° from the previous studies are the most appropriate medial, anterior and posterior acetabular roof arc angles without involvement of the ABSAWBA respectively.

  9. FOUR HEADS OF STERNOCLEIDOMASTOID: A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Sriambika K

    2015-12-01

    Full Text Available During the routine cadaveric dissection, the presence of accessory heads of Sternocleidomastoid was observed on right side. i.e., additional bellies from sternal and clavicle were observed on the right side. These additional slips were innervated by the spinal accessory nerve. These additional slips could have been formed due to unusual splitting in the mesoderm of post-sixth branchial arch during organogenesis. The awareness of variations of sternocleidomastoid muscle is important for Anaesthetists, Plastic surgeons, Orthopaedicians and Dental surgeons while taking muscle flap in reconstructive surgeries and is also important for radiologists while interpreting MR images of this region.

  10. A Canonical Biomechanical Vocal Fold Model

    Science.gov (United States)

    Bhattacharya, Pinaki; Siegmund, Thomas H.

    2012-01-01

    Summary The present article aimed at constructing a canonical geometry of the human vocal fold (VF) from subject-specific image slice data. A computer-aided design approach automated the model construction. A subject-specific geometry available in literature, three abstractions (which successively diminished in geometric detail) derived from it, and a widely used quasi two-dimensional VF model geometry were used to create computational models. The first three natural frequencies of the models were used to characterize their mechanical response. These frequencies were determined for a representative range of tissue biomechanical properties, accounting for underlying VF histology. Compared with the subject-specific geometry model (baseline), a higher degree of abstraction was found to always correspond to a larger deviation in model frequency (up to 50% in the relevant range of tissue biomechanical properties). The model we deemed canonical was optimally abstracted, in that it significantly simplified the VF geometry compared with the baseline geometry but can be recalibrated in a consistent manner to match the baseline response. Models providing only a marginally higher degree of abstraction were found to have significant deviation in predicted frequency response. The quasi two-dimensional model presented an extreme situation: it could not be recalibrated for its frequency response to match the subject-specific model. This deficiency was attributed to complex support conditions at anterior-posterior extremities of the VFs, accentuated by further issues introduced through the tissue biomechanical properties. In creating canonical models by leveraging advances in clinical imaging techniques, the automated design procedure makes VF modeling based on subject-specific geometry more realizable. PMID:22209063

  11. The Undergraduate Biomechanics Experience at Iowa State University.

    Science.gov (United States)

    Francis, Peter R.

    This paper discusses the objectives of a program in biomechanics--the analysis of sports skills and movement--and the evolution of the biomechanics program at Iowa State University. The primary objective of such a course is to provide the student with the basic tools necessary for adequate analysis of human movement, with special emphasis upon…

  12. Factors Related to Students' Learning of Biomechanics Concepts

    Science.gov (United States)

    Hsieh, ChengTu; Smith, Jeremy D.; Bohne, Michael; Knudson, Duane

    2012-01-01

    The purpose of this study was to replicate and expand a previous study to identify the factors that affect students' learning of biomechanical concepts. Students were recruited from three universities (N = 149) located in the central and western regions of the United States. Data from 142 students completing the Biomechanics Concept Inventory…

  13. Biomechanics, Exercise Physiology, and the 75th Anniversary of RQES

    Science.gov (United States)

    Hamill, Joseph; Haymes, Emily M.

    2005-01-01

    The purpose of this paper is to review the biomechanics and exercise physiology studies published in the Research Quarterly for Exercise and Sport (RQES) over the past 75 years. Studies in biomechanics, a relatively new subdiscipline that evolved from kinesiology, first appeared in the journal about 40 years ago. Exercise physiology studies have…

  14. Nerve Cross-Bridging to Enhance Nerve Regeneration in a Rat Model of Delayed Nerve Repair

    Science.gov (United States)

    2015-01-01

    There are currently no available options to promote nerve regeneration through chronically denervated distal nerve stumps. Here we used a rat model of delayed nerve repair asking of prior insertion of side-to-side cross-bridges between a donor tibial (TIB) nerve and a recipient denervated common peroneal (CP) nerve stump ameliorates poor nerve regeneration. First, numbers of retrogradely-labelled TIB neurons that grew axons into the nerve stump within three months, increased with the size of the perineurial windows opened in the TIB and CP nerves. Equal numbers of donor TIB axons regenerated into CP stumps either side of the cross-bridges, not being affected by target neurotrophic effects, or by removing the perineurium to insert 5-9 cross-bridges. Second, CP nerve stumps were coapted three months after inserting 0-9 cross-bridges and the number of 1) CP neurons that regenerated their axons within three months or 2) CP motor nerves that reinnervated the extensor digitorum longus (EDL) muscle within five months was determined by counting and motor unit number estimation (MUNE), respectively. We found that three but not more cross-bridges promoted the regeneration of axons and reinnervation of EDL muscle by all the CP motoneurons as compared to only 33% regenerating their axons when no cross-bridges were inserted. The same 3-fold increase in sensory nerve regeneration was found. In conclusion, side-to-side cross-bridges ameliorate poor regeneration after delayed nerve repair possibly by sustaining the growth-permissive state of denervated nerve stumps. Such autografts may be used in human repair surgery to improve outcomes after unavoidable delays. PMID:26016986

  15. Nerve cross-bridging to enhance nerve regeneration in a rat model of delayed nerve repair.

    Science.gov (United States)

    Gordon, Tessa; Hendry, Michael; Lafontaine, Christine A; Cartar, Holliday; Zhang, Jennifer J; Borschel, Gregory H

    2015-01-01

    There are currently no available options to promote nerve regeneration through chronically denervated distal nerve stumps. Here we used a rat model of delayed nerve repair asking of prior insertion of side-to-side cross-bridges between a donor tibial (TIB) nerve and a recipient denervated common peroneal (CP) nerve stump ameliorates poor nerve regeneration. First, numbers of retrogradely-labelled TIB neurons that grew axons into the nerve stump within three months, increased with the size of the perineurial windows opened in the TIB and CP nerves. Equal numbers of donor TIB axons regenerated into CP stumps either side of the cross-bridges, not being affected by target neurotrophic effects, or by removing the perineurium to insert 5-9 cross-bridges. Second, CP nerve stumps were coapted three months after inserting 0-9 cross-bridges and the number of 1) CP neurons that regenerated their axons within three months or 2) CP motor nerves that reinnervated the extensor digitorum longus (EDL) muscle within five months was determined by counting and motor unit number estimation (MUNE), respectively. We found that three but not more cross-bridges promoted the regeneration of axons and reinnervation of EDL muscle by all the CP motoneurons as compared to only 33% regenerating their axons when no cross-bridges were inserted. The same 3-fold increase in sensory nerve regeneration was found. In conclusion, side-to-side cross-bridges ameliorate poor regeneration after delayed nerve repair possibly by sustaining the growth-permissive state of denervated nerve stumps. Such autografts may be used in human repair surgery to improve outcomes after unavoidable delays.

  16. Large-diameter femoral heads in total hip arthroplasty: an evidence-based review.

    Science.gov (United States)

    Banerjee, Samik; Pivec, Robert; Issa, Kimona; Kapadia, Bhaveen H; Khanuja, Harpal S; Mont, Michael A

    2014-11-01

    Recent advances in the wear characteristics and material properties of highly cross-linked polyethyl-ene and fourth-generation ceramic bearings have led to increasing use of large-diameter (≥ 36 mm) femoral heads in total hip arthroplasty (THA). In this article, we review the current concepts and principles behind use of large-diameter ceramic or cobalt-chromium femoral heads on polyethylene bearings in THA. We specifically review the biomechanics, some of the early concerns about polyethylene wear and rim fractures, recent improvements in material properties of polyethylene and ceramic bearings, dislocation rates, and clinical and functional outcomes of large-diameter heads in THA. Recent literature suggests that the incidence of dislocation has been substantially reduced because of improvements in jump distance and impingement-free range of motion with use of large-diameter heads. Limited evidence suggests excellent short-term and midterm clinical and functional outcomes with these heads.

  17. Acellular nerve allograft promotes selective regeneration

    Institute of Scientific and Technical Information of China (English)

    Haili Xin; Guanjun Wang; Xinrong He; Jiang Peng; Quanyi Guo; Wenjing Xu

    2011-01-01

    Acellular nerve allograft preserves the basilar membrane tube and extracellular matrix, which pro-motes selective regeneration of neural defects via bridging. In the present study, a Sprague Dawley rat sciatic nerve was utilized to prepare acellular nerve allografts through the use of the chemical extraction method. Subsequently, the allograft was transplanted into a 10-mm sciatic nerve defect in Wistar rats, while autologous nerve grafts from Wistar rats served as controls. Compared with autologous nerve grafts, the acellular nerve allografts induced a greater number of degenerated nerve fibers from sural nerves, as well as a reduced misconnect rate in motor fibers, fewer acetyl-choline esterase-positive sural nerves, and a greater number of carbonic anhydrase-positive senso-ry nerve fibers. Results demonstrated that the acellular nerve allograft exhibited significant neural selective regeneration in the process of bridging nerve defects.

  18. Hand function after nerve repair.

    OpenAIRE

    Lundborg, Göran; Rosén, Birgitta

    2007-01-01

    Treatment of injuries to major nerve trunks in the hand and upper extremity remains a major and challenging reconstructive problem. Such injuries may cause long-lasting disabilities in terms of lost fine sensory and motor functions. Nowadays there is no surgical repair technique that can ensure recovery of tactile discrimination in the hand of an adult patient following nerve repair while very young individuals usually regain a complete recovery of functional sensibility. Post-traumatic nerve...

  19. Ergonomic Evaluation of Biomechanical Hand Function

    Directory of Open Access Journals (Sweden)

    Kyung-Sun Lee

    2015-03-01

    Full Text Available The human hand is a complex structure that performs various functions for activities of daily living and occupations. This paper presents a literature review on the methodologies used to evaluate hand functions from a biomechanics standpoint, including anthropometry, kinematics, kinetics, and electromyography (EMG. Anthropometry describes the dimensions and measurements of the hand. Kinematics includes hand movements and the range of motion of finger joints. Kinetics includes hand models for tendon and joint force analysis. EMG is used on hand muscles associated with hand functions and with signal-processing technology.

  20. BIOMECHANICS AND PATHOMECHANICS OF THE PATELLOFEMORAL JOINT.

    Science.gov (United States)

    Loudon, Janice K

    2016-12-01

    The patellofemoral joint is a joint that can be an area of concern for athletes of various sports and ages. The joint is somewhat complex with multiple contact points and numerous tissues that attach to the patella. Joint forces are variable and depend on the degree of knee flexion and whether the foot is in contact with the ground. The sports medicine specialist must have a good working knowledge of the anatomy and biomechanics of the patellofemoral joint in order to treat it effectively.