The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Robert M. Szabo - One of the best experts on this subject based on the ideXlab platform.
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Displacement and strain of the Median Nerve at the wrist.
The Journal of hand surgery, 1997Co-Authors: Brian K. Bay, Neil A. Sharkey, Robert M. SzaboAbstract:Median Nerve displacement and strain in the carpal tunnel region were measured as functions of wrist position and carpal tunnel pressure in 5 cadaver forearms during simulated active finger flexion. The positions of spherical stainless-steel markers embedded within the Median Nerve and flexor digitorum superficialis of the long finger were measured in 3 dimensions by a radiographic direct linear transformation technique. Each limb was tested in 3 wrist positions (60° extension, neutral, and 60° flexion) and 4 carpal tunnel pressures (0, 30, 60, and 90 mmHg). Carpal tunnel pressure was controlled with a balloon angiocatheter inserted deep to the flexor digitorum profundus. The ratio of Median Nerve to flexor tendon excursion was linear and was affected by wrist position but not carpal tunnel pressure. Patterns of strain in the Median Nerve proximal to the flexor retinaculum were different from those of strain within the carpal tunnel. Nerve strains were affected by wrist position, but carpal tunnel pressure had no effect. The hydrostatic pressure effect associated with carpal tunnel syndrome does not appear to influence Median Nerve kinetics or kinematics for the wrist positions studied.
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Median Nerve displacement through the carpal canal
The Journal of hand surgery, 1994Co-Authors: Robert M. Szabo, Brian K. Bay, Neil A. Sharkey, Chris GautAbstract:Abstract We determined the direct relationships between wrist position and displacement of the Median Nerve during active contraction of the flexor tendons at the wrist with an intact, transected transverse carpal ligament (TCL). Nine fresh cadavers were mounted in an apparatus to allow variable wrist position. Excursions of the tendons and displacement of the Median Nerve were measured by tracking markers with a video camera. Each limb was tested at 0°, 30°, and 60° of wrist extension before and after release of the TCL. Excursion of the flexor tendons required for full finger flexion ranged from 2.3 to 3.1 cm (mean, 3 cm). Median Nerve displacement ranged from 0.9 to 1.4 cm (mean, 1 cm). The relationship between Median Nerve and flexor tendon excursion was consistently linear. Finger motion alone allows for Median Nerve displacement after surgery in the carpal tunnel.
Ayman Mohamed Ebied - One of the best experts on this subject based on the ideXlab platform.
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Split Median Nerve.
Microsurgery, 1999Co-Authors: Ayman Mohamed EbiedAbstract:Carpal tunnel syndrome is encountered frequently in the every day practice for many orthopaedic surgeons and neurosurgeons. However, the rate of recurrence or incomplete relief is high and difficult to treat. This may be related to the high percent of anomalies of the Median Nerve and its surrounding tissues. A case of a split Median Nerve entrapped by an abnormally inserted palmaris longus muscle is presented. The case is discussed and a conclusion of safer standard surgical release is recommended, especially in doubtful cases.
Krishna Swami Gajendra - One of the best experts on this subject based on the ideXlab platform.
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Variant formation and course of the Median Nerve
2010Co-Authors: Ajay Ratnakarrao, Krishna Swami GajendraAbstract:Many formative variations of Median Nerve are known but this variant formation and course of Median Nerve is rare. A variant formation of Median Nerve was noted in the left axilla and arm of a male cadaver, in the form of formation of Median Nerve behind the third part of axillary artery and its course in arm entirely behind the brachial artery. There may be compression of axillary artery due to the roots of the Nerve passing around the artery. Also there may be compression of Median Nerve between the fork of axillary artery and its branch. This variation may be clinically important because symptoms of Median Nerve compression arising from similar variations are often confused with more common causes such as radiculopathy and carpal tunnel syndrome. © IJAV. 2010; 3: 93–94.
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A rare variant formation of the Median Nerve
2010Co-Authors: Ajay Ratnakarrao, Krishna Swami GajendraAbstract:Brachial plexus, due to its complicated formation frequently shows variations. Many formative variations of Median Nerve are reported. A variant formation of Median Nerve was noted in the right axilla and arm of a male cadaver, in the form of three accessory communications between lateral and medial roots of Median Nerve. All the accessory communications passed from lateral to medial root. Different types of variations of Median Nerve formation are documented but the one found in present study is rare. There may be compression of axillary artery due to the accessory communication passing around the artery. Also injury in this region may lead to unusual clinical picture. A well-informed clinician must know about the variations usually seen in the brachial plexus and its branches to correctly examine a clinical case and also to explain unusual clinical signs seen when one come across a lesion in a variant brachial plexus. © IJAV. 2010; 3: 138–140.
Brian K. Bay - One of the best experts on this subject based on the ideXlab platform.
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Displacement and strain of the Median Nerve at the wrist.
The Journal of hand surgery, 1997Co-Authors: Brian K. Bay, Neil A. Sharkey, Robert M. SzaboAbstract:Median Nerve displacement and strain in the carpal tunnel region were measured as functions of wrist position and carpal tunnel pressure in 5 cadaver forearms during simulated active finger flexion. The positions of spherical stainless-steel markers embedded within the Median Nerve and flexor digitorum superficialis of the long finger were measured in 3 dimensions by a radiographic direct linear transformation technique. Each limb was tested in 3 wrist positions (60° extension, neutral, and 60° flexion) and 4 carpal tunnel pressures (0, 30, 60, and 90 mmHg). Carpal tunnel pressure was controlled with a balloon angiocatheter inserted deep to the flexor digitorum profundus. The ratio of Median Nerve to flexor tendon excursion was linear and was affected by wrist position but not carpal tunnel pressure. Patterns of strain in the Median Nerve proximal to the flexor retinaculum were different from those of strain within the carpal tunnel. Nerve strains were affected by wrist position, but carpal tunnel pressure had no effect. The hydrostatic pressure effect associated with carpal tunnel syndrome does not appear to influence Median Nerve kinetics or kinematics for the wrist positions studied.
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Median Nerve displacement through the carpal canal
The Journal of hand surgery, 1994Co-Authors: Robert M. Szabo, Brian K. Bay, Neil A. Sharkey, Chris GautAbstract:Abstract We determined the direct relationships between wrist position and displacement of the Median Nerve during active contraction of the flexor tendons at the wrist with an intact, transected transverse carpal ligament (TCL). Nine fresh cadavers were mounted in an apparatus to allow variable wrist position. Excursions of the tendons and displacement of the Median Nerve were measured by tracking markers with a video camera. Each limb was tested at 0°, 30°, and 60° of wrist extension before and after release of the TCL. Excursion of the flexor tendons required for full finger flexion ranged from 2.3 to 3.1 cm (mean, 3 cm). Median Nerve displacement ranged from 0.9 to 1.4 cm (mean, 1 cm). The relationship between Median Nerve and flexor tendon excursion was consistently linear. Finger motion alone allows for Median Nerve displacement after surgery in the carpal tunnel.
Lisa D Hobsonwebb - One of the best experts on this subject based on the ideXlab platform.
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Median Nerve ultrasonography in carpal tunnel syndrome findings from two laboratories
Muscle & Nerve, 2009Co-Authors: Lisa D Hobsonwebb, Luca PaduaAbstract:Ultrasonographic (US) enlargement of the Median Nerve at the wrist is known to be consistent with carpal tunnel syndrome (CTS), although the effects of different measurement techniques, equipment, and patient populations remain unknown. The purpose of this study was to examine the similarities and differences of US findings in CTS between two electromyography (EMG) laboratories. In 2006 and 2007, US measurements of the Median Nerve were recorded independently and statistically analyzed in patients with CTS at two EMG laboratories (Duke University, Durham, NC, USA, and Universita Cattolica del Sacro Cuore, Rome, Italy). Patient age, Median Nerve area in the forearm, and neurophysiologic score did not differ significantly between the two laboratories. The North Carolina group had a larger Median Nerve area at the wrist and wrist-to-forearm ratio than the Italian group, although both were elevated in reference to established values for the diagnosis of CTS. Median Nerve US is less susceptible to differences between laboratories than previously thought, permitting greater generalization of findings.
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the ultrasonographic wrist to forearm Median Nerve area ratio in carpal tunnel syndrome
Clinical Neurophysiology, 2008Co-Authors: Lisa D Hobsonwebb, Janice M Massey, Vern C Juel, Donald B SandersAbstract:Abstract Objective Peripheral Nerve ultrasound is an emerging tool in the diagnosis of carpal tunnel syndrome (CTS). Although numerous publications have cited an increased Median Nerve area at the wrist to be the diagnostic of CTS, there has been considerable variability in the published normal values for this measurement. Our objective is to collect data on the wrist-to-forearm ratio (WFR) of Median Nerve area in patients with CTS and healthy controls. Methods Patients with electrodiagnostically proven CTS underwent ultrasonography of the Median Nerve at the wrist and forearm. The Median Nerve area was measured at these points and compared to values from asymptomatic volunteers. Results The WFR of Median Nerve area in asymptomatic volunteers was 1.0 ± 0.1. The WFR in patients presenting with CTS was 2.1 ± 0.5. Conclusions The WFR in patients with CTS is elevated as compared to asymptomatic controls. A WFR of ⩾1.4 gave 100% sensitivity for detecting patients with CTS while using only Median Nerve area at the wrist resulted in a sensitivity of 45–93%, depending on the cut-off value used. Significance The WFR of Median Nerve area promises to be a valid means of diagnosing CTS, and may be superior to measuring Median Nerve area at the wrist alone.
