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Median Nerve (median + nerve)
Terms modified by Median Nerve Selected AbstractsUltrasonographic Reference Values for Assessing the Normal Median Nerve in AdultsJOURNAL OF NEUROIMAGING, Issue 1 2009Michael S. Cartwright MD ABSTRACT BACKGROUND AND PURPOSE Several studies have evaluated the cross-sectional area of the median nerve at the wrist, but none have examined other sites along the median nerve. Nerve enlargement has been demonstrated in entrapment, hereditary and acquired neuropathies, as well as with intraneural masses, and cross-sectional area reference values at sites along the nerve will help in the evaluation of these conditions. In addition, muscle intrusion into the carpal tunnel has been implicated in carpal tunnel syndrome, but the normal amount of muscle intrusion has not been quantified. METHODS Fifty asymptomatic volunteers (100 arms) were evaluated to determine the mean cross-sectional area of the median nerve at 6 sites and the mean amount of muscle intruding into the carpal tunnel. RESULTS The cross-sectional area of the nerve was consistent along its course (7.5 to 9.8 mm2). The amount of muscle within the carpal tunnel varied greatly, with the mean area of flexor digitorum being 15.5 mm2 and lumbricals 13.5 mm2. CONCLUSIONS These reference values are necessary for advancing the field of neuromuscular ultrasound, because they facilitate studies of the median nerve in conditions such as entrapment, hereditary neuropathy, acquired neuropathy, and intraneural masses. [source] ELECTROPHYSIOLOGICAL ABNORMALITIES IN DIABETIC PATIENTSJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2000B. Lanzillo We studied 476 patients affected by diabetes: 166 male (mean age 61.6 ± 10 years, range 27,91) and 310 female (mean age 61.5 ± 8.4 years, range 25,82). Mean disease duration was 11.3 ± 7.6 years, range 0.3,37). All patients underwent surface motor and sensory nerve conduction along median, popliteal, and sural nerve. Results. Median nerve: in 3.1% of subjects sensory action potentials (SAP) was absent; sensory nerve conduction velocity (SNCV) was reduced in 41.8% in distal segment and in 27.5% in the proximal segment. Motor nerve conduction (MNCV) was reduced in 29.9% of the subjects. Sural nerve: SAP was absent in 24.4% and SNCV was reduced in 32.7%. Popliteal nerve: MNCV was abnormal in 30.4% of the subjects. Combining electrophysiological data we observed that: 1. 28.6% of the subjects resulted normal 2. 12.8% were affected by a lower limbs sensory neuropathy 3. 0.2% had a lower limbs motor neuropathy 4. 5.9% had a lower limbs sensory-motor neuropathy 5. 6.1% had a diffused sensory neuropathy 6. 30.2% had a diffused sensory-motor neuropathy 7. 16.2% had a carpal tunnel syndrome. Patients were divided in 2 groups: patients with and patients without neuropahy: the latter showed a significantly shorter disease duration (12.7 ± 8.1 vs 9.0 ± 6.3; p < 0.0001). In addition, we observed a significant correlation between disease duration and distal latency, median and popliteal MNCV, and SNCV in median and sural nerve (Regression test; p < 0.0001). Patients on insulin showed a longer disease duration and more severe electrophysiological abnormalities. [source] Effect of acute hyperglycaemia on sensory processing in diabetic autonomic neuropathyEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 10 2010Jens B. Frøkjær Eur J Clin Invest 2010; 40 (10): 883,886 Abstract Background, Acute hyperglycaemia is known to increase gastrointestinal (GI) sensitivity in healthy subjects and may contribute to the increased prevalence of GI symptoms in diabetes patients. The aim of this study was to evaluate the effect of acute hyperglycaemia on perception and brain responses to painful visceral and somatic stimuli in diabetic patients. Materials and methods, The sensitivity and evoked brain potentials (EPs) to electrical oesophageal and median nerve stimulations were assessed in 14 type-1 diabetes patients with autonomic neuropathy and GI symptoms using a hyperinsulinaemic clamp at 6 and 15 mM. Results, No differences between the normo- and hyperglycaemic conditions were found in sensitivity to both oesophageal (P = 0·72) and median nerve (P = 0·66) stimulations. The latencies and amplitudes of EPs did not differ between the normo- and hyperglycaemic conditions following oesophageal (P = 0·53 and 0·57) and median nerve (P = 0·78 and 0·52) stimulations. Conclusions, Acute hyperglycaemia itself does not contribute to the sensations in patients with longstanding diabetes and autonomic neuropathy. Any potential sensory effects of acute hyperglycaemia can likely be blurred by the neuropathic-like changes in the sensory nervous system. [source] Differences between the effects of three plasticity inducing protocols on the organization of the human motor cortexEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2006Karin Rosenkranz Abstract Several experimental protocols induce lasting changes in the excitability of motor cortex. Some involve direct cortical stimulation, others activate the somatosensory system and some combine motor and sensory stimulation. The effects usually are measured as changes in amplitude of the motor-evoked-potential (MEP) or short-interval intracortical inhibition (SICI) elicited by a single or paired pulses of transcranial magnetic stimulation (TMS). Recent work has also tested sensorimotor organization within the motor cortex by recording MEPs and SICI during short periods of vibration applied to single intrinsic hand muscles. Here sensorimotor organization is focal: MEPs increase and SICI decreases in the vibrated muscle, whilst the opposite occurs in neighbouring muscles. In six volunteers we compared the after effects of three protocols that lead to lasting changes in cortical excitability: (i) paired associative stimulation (PAS) between a TMS pulse and an electrical stimulus to the median nerve; (ii) motor practice of rapid thumb abduction; and (iii) sensory input produced by semicontinuous muscle vibration, on MEPs and SICI at rest and on the sensorimotor organization. PAS increased MEP amplitudes, whereas vibration changed sensorimotor organization. Motor practice had a dual effect and increased MEPs as well as affecting sensorimotor organization. The implication is that different protocols target different sets of cortical circuits. We speculate that protocols that involve repeated activation of motor cortical output lead to lasting changes in efficacy of synaptic connections in output circuits, whereas protocols that emphasize sensory inputs affect the strength of sensory inputs to motor circuits. [source] Movement gating of beta/gamma oscillations involved in the N30 somatosensory evoked potentialHUMAN BRAIN MAPPING, Issue 5 2009Ana Maria Cebolla Abstract Evoked potential modulation allows the study of dynamic brain processing. The mechanism of movement gating of the frontal N30 component of somatosensory evoked potentials (SEP) produced by the stimulation of the median nerve at wrist remains to be elucidated. At rest, a power enhancement and a significant phase-locking of the electroencephalographic (EEG) oscillation in the beta/gamma range (25,35 Hz) are related to the emergence of the N30. The latter was also perfectly identified in presence of pure phase-locking situation. Here, we investigated the contribution of these rhythmic activities to the specific gating of the N30 component during movement. We demonstrated that concomitant execution of finger movement of the stimulated hand impinges such temporal concentration of the ongoing beta/gamma EEG oscillations and abolishes the N30 component throughout their large topographical extent on the scalp. This also proves that the phase-locking phenomenon is one of the main actors for the N30 generation. These findings could be explained by the involvement of neuronal populations of the sensorimotor cortex and other related areas, which are unable to respond to the phasic sensory activation and to phase-lock their firing discharges to the external sensory input during the movement. This new insight into the contribution of phase-locked oscillation in the emergence of the N30 and in its gating behavior calls for a reappraisal of fundamental and clinical interpretation of the frontal N30 component. Hum Brain Mapp 2009. © 2008 Wiley-Liss, Inc. [source] Neural connectivity in hand sensorimotor brain areas: An evaluation by evoked field morphologyHUMAN BRAIN MAPPING, Issue 2 2005Franca Tecchio Abstract The connectivity pattern of the neural network devoted to sensory processing depends on the timing of relay recruitment from receptors to cortical areas. The aim of the present work was to uncover and quantify the way the cortical relay recruitment is reflected in the shape of the brain-evoked responses. We recorded the magnetic somatosensory evoked fields (SEF) generated in 36 volunteers by separate bilateral electrical stimulation of median nerve, thumb, and little fingers. After defining an index that quantifies the shape similarity of two SEF traces, we studied the morphologic characteristics of the recorded SEFs within the 20-ms time window that followed the impulse arrival at the primary sensory cortex. Based on our similarity criterion, the shape of the SEFs obtained stimulating the median nerve was observed to be more similar to the one obtained from the thumb (same median nerve innervation) than to the one obtained from the little finger (ulnar nerve innervation). In addition, SEF shapes associated with different brain regions were more similar within an individual than between subjects. Because the SEF morphologic characteristics turned out to be quite diverse among subjects, we defined similarity levels that allowed us to identify three main classes of SEF shapes in normalcy. We show evidence that the morphology of the evoked response describes the anatomo-functional connectivity pattern in the primary sensory areas. Our findings suggest the possible existence of a thalamo-cortico-thalamic responsiveness loop related to the different classes. Hum Brain Mapp 24:99,108, 2005. © 2004 Wiley-Liss, Inc. [source] Microneurography of human median nerveJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2005Mehmet Bilgen PhD Abstract Purpose To examine the possibility of performing high-resolution MRI (microneurography) on peripheral nerves. Materials and Methods A specific radio frequency (RF) coil was developed to probe the human median nerve at a magnetic field strength of 9.4 T and tested on three excised samples by acquiring microneurograms. Results The microneurograms revealed neuronal tissue constituents at subfascicular level. The contrast features on proton-density and T1- and T2-weighted images were described and compared. The microscopic water movement was quantified using diffusion weighting parallel and orthogonal to the neuronal fiber orientation. The characteristics of anisotropic diffusion in the median nerve were comparable to those reported from other biological tissues (white matter and kidney). Conclusion The results overall suggest that microneurography might provide new noninvasive insights into microscopic gross anatomy of the peripheral nerve, injury evaluation, and efficacy of repair, although the feasibility at current clinically relevant field strengths is yet to be determined. J. Magn. Reson. Imaging 2005;21:826,830. © 2005 Wiley-Liss, Inc. [source] Ultrasonographic Reference Values for Assessing the Normal Median Nerve in AdultsJOURNAL OF NEUROIMAGING, Issue 1 2009Michael S. Cartwright MD ABSTRACT BACKGROUND AND PURPOSE Several studies have evaluated the cross-sectional area of the median nerve at the wrist, but none have examined other sites along the median nerve. Nerve enlargement has been demonstrated in entrapment, hereditary and acquired neuropathies, as well as with intraneural masses, and cross-sectional area reference values at sites along the nerve will help in the evaluation of these conditions. In addition, muscle intrusion into the carpal tunnel has been implicated in carpal tunnel syndrome, but the normal amount of muscle intrusion has not been quantified. METHODS Fifty asymptomatic volunteers (100 arms) were evaluated to determine the mean cross-sectional area of the median nerve at 6 sites and the mean amount of muscle intruding into the carpal tunnel. RESULTS The cross-sectional area of the nerve was consistent along its course (7.5 to 9.8 mm2). The amount of muscle within the carpal tunnel varied greatly, with the mean area of flexor digitorum being 15.5 mm2 and lumbricals 13.5 mm2. CONCLUSIONS These reference values are necessary for advancing the field of neuromuscular ultrasound, because they facilitate studies of the median nerve in conditions such as entrapment, hereditary neuropathy, acquired neuropathy, and intraneural masses. [source] Longitudinal excursion and strain in the median nerve during novel nerve gliding exercises for carpal tunnel syndromeJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 7 2007Michel W. Coppieters Abstract Nerve and tendon gliding exercises are advocated in the conservative and postoperative management of carpal tunnel syndrome (CTS). However, traditionally advocated exercises elongate the nerve bedding substantially, which may induce a potentially deleterious strain in the median nerve with the risk of symptom exacerbation in some patients and reduced benefits from nerve gliding. This study aimed to evaluate various nerve gliding exercises, including novel techniques that aim to slide the nerve through the carpal tunnel while minimizing strain ("sliding techniques"). With these sliding techniques, it is assumed that an increase in nerve strain due to nerve bed elongation at one joint (e.g., wrist extension) is simultaneously counterbalanced by a decrease in nerve bed length at an adjacent joint (e.g., elbow flexion). Excursion and strain in the median nerve at the wrist were measured with a digital calliper and miniature strain gauge in six human cadavers during six mobilization techniques. The sliding technique resulted in an excursion of 12.4 mm, which was 30% larger than any other technique (p,,,0.0002). Strain also differed between techniques (p,,,0.00001), with minimal peak values for the sliding technique. Nerve gliding associated with wrist movements can be considerably increased and nerve strain substantially reduced by simultaneously moving neighboring joints. These novel nerve sliding techniques are biologically plausible exercises for CTS that deserve further clinical evaluation. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:972,980, 2007 [source] Localization and changes of intraneural inflammatory cytokines and inducible-nitric oxide induced by mechanical compressionJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2005Shigeru Kobayashi Abstract Study design: Investigation of intraneural inflammation induced by mechanical compression. Objectives: In order to investigate the mechanism of neuropathy, this study used a median nerve compression model in dogs. Immunohistochemistry was used to examine the localization and changes of inflammatory cytokines and nitric oxide (NO). Summary of background data: The manifestation of pain at sites of inflammation has a close relationship with the release of mediators from macrophages such as interleulin-1 (IL-1) and tumor necrosis factor-, (TNF-,), as well as with NO. However, the mediators involved in inflammation of nerve due to mechanical compression remain almost unknown. Methods: In this study, the median nerve of dogs was compressed with a clip for three weeks to observe the changes caused by compression. Immunohistochemistry was done by the avidin-biotin-peroxidase complex method to observe the changes of T cells (CD45) and macrophages (Mac-1) after compression. Antibodies against IL-,, TNF-,, and inducible nitric oxide synthesis (i-NOS) were used to examine the localization and changes of these mediators caused by nerve compression. Results: In control animals, resident T cells were detected, but there were no macrophages. IL-1, was positive in the Schwann cells and vascular endothelial cells. However, no cells showed TNF-, or i-NOS positively. After nerve compression, numerous T cells and macrophages appeared among the demyelinized nerve fibers. The macrophages were positive for IL-1,, TNF-, and i-NOS. Conclusion: Inflammatory cytokines and NO may be involved in intraneural inflammatory changes arising from mechanical compression. Such mediators may be of importance in the manifestation of neuropathy. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source] The role of cutaneous sensation in the motor function of the handJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 4 2004Ayman M. Ebied Abstract We studied the effect of abolishing cutaneous sensation (by infiltrating local anaesthetic around the median nerve at the wrist) on the ability of 10 healthy volunteers (a) to maintain a submaximal isometric pinch-grip force for 30 s without visual feedback, and (b) to perform a fine finger-manipulation ,handwriting" task. Blocking cutaneous sensation had no effect on ability to maintain pinch force, suggesting that muscle afferents have the major role in force-control feedback. However, a near-linear fall in force, present with or without block (mean slope = ,1.3 ± 0.2% s,1), which cannot be attributed to motor fatigue, reveals a shortcoming of the afferent feedback system. Blocking cutaneous sensation did impair ability to perform the more demanding writing task, as judged by an 18 ± 6% increase in the length of the path between target points, a 22 ± 9% increase in the duration of the movement and a 63 ± 24% in ,normalised averaged rectified jerk", an averaged time-derivative of acceleration (all significantly nonzero, P < 0.04). These experiments demonstrate the relative importance of muscular and cutaneous afferent feedback on two aspects of hand performance, and provide a way to quantify the deficit resulting from the lack of cutaneous sensation. © 2003 Published by Elsevier Ltd. on behalf of Orthopaedic Research Society. All rights reserved. [source] Treating nerves: a call to armsJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 2 2008Richard A. C. Hughes Abstract The process of proving that new treatments for peripheral nerve diseases work has often been slow and inefficient. The lack of adequate evidence for some existing treatments has been highlighted by Cochrane systematic reviews. This article uses four different conditions to illustrate the need for more research. Both corticosteroid injections and surgical decompression of the median nerve are efficacious in carpal tunnel syndrome, but whether corticosteroid injections avoid the need for operation needs to be discovered. Corticosteroids are efficacious for Bell's palsy, but the role of antiviral agents needs clarification, which should come from ongoing trials. Intravenous immunoglobulin (IVIg) and plasma exchange are both efficacious in Guillain-Barré syndrome, but corticosteroids are not. More trials are needed to discover the best dose of IVIg in severe cases and whether mild cases need treatment. In chronic inflammatory demyelinating polyradiculoneuropathy, corticosteroids, IVIg and plasma exchange are all efficacious, at least in the short term, but trials are needed to discover whether and which other immunosuppressive agents help. The Peripheral Nerve Society has formed a standing committee, the Inflammatory Neuropathy Consortium (http://pns.ucsd.edu/INC.htm), to facilitate the trials needed to answer the remaining questions in the inflammatory neuropathies. [source] Electrophysiological findings of peripheral neuropathy in newly diagnosed type II diabetes mellitusJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 4 2005Eugenia Rota Abstract This study was aimed at assessing the electrophysiological signs of peripheral neuropathy in diabetes mellitus (DM) type II patients at diagnosis. Nerve conduction studies (NCS) of median, ulnar, peroneal, tibial and sural nerves were performed in 39 newly diagnosed DM subjects and compared to those of 40 healthy controls. Metabolic indices were also investigated. Electrophysiological alterations were found in 32 (82%) of the DM patients, and more than half of them (62.2%) showed multiple (two to five) abnormal parameters. Because most of the subjects (84.4%) had from two to five nerves involved, these alterations were widespread in the seven nerves evaluated. Forty-two percent of the patients had NCS alterations suggestive of distal median mononeuropathy, implying that metabolic factors in DM make the median nerve more susceptible to focal entrapment. A reduced sensory nerve action potential (SNAP) amplitude was observed in the median nerve in 70% of the patients, in the ulnar in 69% and in the sural nerve only in 22%. In the presence of a decrease in the SNAP amplitude of the ulnar or median nerve, the SNAP amplitude of the sural nerve was normal in 82 or 80% of the subjects, respectively. This finding may be in keeping with a distal involvement of the sensory fibres, as explored by routine median or ulnar NCS. No correlation was found between metabolic indices and NCS parameters. In conclusion, a high percentage of newly diagnosed DM patients show signs of neuropathy, and upper limb nerve sensory NCS seem to be more sensitive in detecting it than lower limb NCS. [source] A very large Schwannoma originating from the median nerve in carpal tunnelJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 3 2004Hakan Gündes Abstract Schwannomas are common benign nerve tumors occurring in the peripheral nerves. A very large schwannoma of more than 5 years duration, originating from the median nerve in the carpal tunnel in a 38-year-old woman, is reported. There was a painful mass, 60 mm in length and 42 mm in diameter, on the palm without signs of sensory disturbance or atrophy on the thenar muscles. Surgical removal was performed under high-power magnification by separating the sensory and motor fascicles from the tumor. Histological examination resulted in a Schwannoma. At 4-year follow-up, the patient was asymptomatic with excellent relief of symptoms. The tumor did not recur. Although cases have been reported in the literature, this is one of the largest ever described without any neurologic deficit. [source] Abstracts of the 8th Meeting of the Italian Peripheral Nerve Study Group: 81JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2003S Lori Symptomatic neuropathy in young patients with type 1 Diabetes Mellitus (t1DM) is rare but subclinical peripheral alterations can be assessed by electroclinical evaluation. This study aimed to assess prevalence of clinical and subclinical peripheral neuropathy in patients with t1DM. Motor and/or sensory nerve conduction studies of both median, ulnar, peroneal, tibial and sural nerves and standard clinical examination of peripheral nervous system were performed in 83 patients (27 females and 56 males) with diabetes onset since five years. The mean age of patients was 19.89 (range 9,28.3) years, the mean disease duration was 9.61(range 4.4,19.3) and the mean age at the onset of diabetes was 9.02 (range 0.8,23.5). Five patients (6.02 %) had both symptomatic (light clinical abnormalities as paresthesias and mild reduction of vibratory sensibility) and electrophysiologic neuropathy and six (7.2 %) with mild abnormal nerve conduction studies were totally asymptomatic (subclinical neuropathy). The majority of symptoms and electrophysiological alterations were found on the lower limbs. Only two patients had a minimal distal neuropathy of median nerve. No patients showed laboratory evidence of early renal complications or systemic hypertension; 5 (6.02 %) had early diabetic retinal abnormalities as microaneurisms, seen by fundus examination. Analysis of sex, age of onset, duration of diabetes, age at the date of electrophysiologic examination, Hemoglobin A1c (mean level of the last two years), association with retinal abnormalities and clinical assessment was performed (Fisher Exact Test, ANOVA). No correlation was found with the age at the onset, retinal abnormalities and glycaemic control index. Peripheral neuropathy was significantly related with patient age at the date of electrophysiological study and duration of t1DM. [source] Intrinsic haemangioma of the median nerve: Report of a case and review of the literatureMICROSURGERY, Issue 2 2008Marios D. Vekris M.D. Intrinsic haemangioma of the median nerve is an extremely rare tumor that represents a challenge to diagnose and treat. Only a few cases have been reported in the literature. We present a 10-year-old girl who was diagnosed having an intrinsic haemangioma of the median nerve and treated with total surgical resection of the tumor, under high magnification, using microneurolysis and without the need to resect and graft the median nerve. Three years later, the patient is free of symptoms and no recurrence of the mass was noticed. © 2008 Wiley-Liss, Inc. Microsurgery, 2008. [source] Microsurgical reconstruction of brachial artery injuries in displaced supracondylar fracture humerus in childrenMICROSURGERY, Issue 7 2006Hassan H. Noaman M.D. Between March 2000 and March 2005, 840 children with grade III supracondylar humeral fractures presented for treatment, consecutively at our hospital. One hundred twenty had absent or diminished (detected by Doppler but not palpable) radial pulse on initial examination. Eighty-nine of these 120 children recovered pulse (palpable) after closed reduction and percutaneous pinning of the fracture. The remaining 31 children had persistent absent radial pulse. Twenty-two of the 31 children had median nerve signs. Each of these 31 children was explored. The intraoperative findings were intact median nerve in all cases (neuropraxia), traumatic aneurysm with thrombus formation in 17 cases, complete injury of the brachial artery in 8 cases (loss of continuity), thrombosis in 3 cases, partial tear in 2 cases, and brachial artery entrapment in the fracture site in 1 case. Microsurgical reconstruction of the 31 brachial arteries was done as the following: reversed vein graft for 8 cases, excision and repair in 17 cases, partial repair in 2 cases, thrombectomy in 3 cases, and release of the brachial artery from the fracture site in 1 case. The average follow up was 26 months range (6,60) months. All children had excellent to good functional and cosmetic outcome except one who had Volkman's ischemic contracture, treated later by free functioning gracilis muscle transfer. © 2006 Wiley-Liss, Inc. Microsurgery, 2006. [source] Transfer of brachialis branch of musculocutaneous nerve for finger flexion: Anatomic study and case reportMICROSURGERY, Issue 5 2004Yudong Gu M.D. Based on an anatomic study, a transfer of the brachialis muscle branch of the musculocutaneous nerve (BMBMCN) to finger flexor functional fascicles of the median nerve was designed. Preliminary results of clinical application of this new procedure are reported. Dissection of 32 cadaver upper limbs revealed that BMBMCN derives from the musculocutaneous nerve at the distal 1/3 upper arm level. Mostly it is of single-branch type, with an average dissectable length of 5.2 cm. At this level, functional fascicles of finger flexors are located at the posterior 1/3 of the median nerve. BMBMCN can be directly coapted to these finger flexion fascicles. In one case of brachial plexus lower trunk injury, this neurotization procedure was done. No impairment of elbow flexion and wrist flexion was found postoperatively. Recovery of finger and thumb flexion was seen 1 year postoperatively. This neurotization is safe and effective for treating lower trunk injuries. © 2004 Wiley-Liss, Inc. Microsurgery 24:1,5, 2004. [source] Sonographic measurements of longitudinal median nerve sliding in patients following nerve repairMUSCLE AND NERVE, Issue 3 2010Ertan Erel FRCS Abstract Nerve sliding may be restricted following nerve repair. This could result in increased tension across the repair site and lead to poor functional recovery of the nerve. Ultrasound was used to examine longitudinal median nerve sliding in 10 patients who had previously undergone nerve repair surgery following complete division of the median nerve. The median longitudinal movement in the forearm in response to metacarpophalangeal (MCP) joint movements was 2.15 mm on the injured side, compared with 2.54 mm on the uninjured side, a difference that was significant. There was a significant reduction in nerve sliding following repair (median = 8%, range ,8% to 54%; P = 0.02), which correlated with time from injury to surgery (rho = 0.87; P = 0.001). These results indicate that ultrasound can be used as an adjunct assessment tool to monitor both morphology and sliding of the nerve through the repair site. It may have future application in the investigation of patients with persisting functional impairment following primary nerve repair. Muscle Nerve, 2009 [source] Vibration prolongs the cortical silent period in an antagonistic muscleMUSCLE AND NERVE, Issue 6 2009Christian Binder MD Abstract We tested whether the silent period, an indicator of inhibitory neuronal activity, is modulated by muscle vibration. Vibration was applied to the right extensor carpi radialis (ECR) muscle in 17 healthy subjects and, as a control experiment, to the dorsal terminal phalanges in 5 subjects. Data before vibration were compared with those during vibration. The cortical silent period (CSP) was evoked by transcranial magnetic stimuli (TMS) during voluntary wrist flexion or during voluntary wrist extension. TMS-evoked motor potentials (MEPs) of the flexor carpi radialis (FCR) muscle were recorded during muscle relaxation. The mixed nerve silent period (MNSP) was obtained by electrical stimulation of the median nerve during wrist flexion. ECR vibration induced a significant prolongation of the CSP in FCR. CSP increases induced by vibration of the dorsal terminal phalanges were significantly less pronounced. In ECR, the CSP tended to be shortened. MEPs and MNSP remained unchanged. We conclude that vibration enhances inhibitory neuronal properties in a non-vibrated antagonistic muscle, presumably at a supraspinal level. These results may be relevant for the treatment of spasticity of the upper extremity. Muscle Nerve, 2009 [source] Simplified orthodromic inching test in mild carpal tunnel syndromeMUSCLE AND NERVE, Issue 12 2001Paul Seror MD Abstract This prospective study was undertaken to determine the clinical relevance, reliability, sensitivity, and specificity of the orthodromic inching test with 2-cm incremental study of the median nerve over the four intracarpal centimeters in 50 control and 50 successive (unselected) patient wrists with mild carpal tunnel syndrome (CTS). In controls, the mean maximum conduction delay per 2 cm (CD/2cm) was 0.445 ± 0.04 ms, and abnormality was defined as at least one CD/2cm exceeding the mean + 2.5 SD of the normal CD/2cm. This yielded a specificity of 98%. In patients with mild unselected CTS, this simplified orthodromic inching test (SOIT) detected the median nerve lesion at the wrist in 47 cases (sensitivity = 94%). The SOIT detected 15 more CTS cases than did the orthodromic median-ulnar latency difference of the 4th digit (Chi square = 13; P = .002). Thus, the SOIT was as effective as an incremental study every centimeter over 10 cm, and the time required for the test allows its routine use when other electrodiagnostic tests fail to reveal any median nerve impairment. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1595,1600, 2001 [source] Sensory potentials evoked by tactile stimulation of different indentation velocities at the finger and palmMUSCLE AND NERVE, Issue 9 2001Masayuki Baba MD Abstract Previous studies suggest that the rate of indentation of a tactile probe determines which skin mechanoreceptors are activated. To further investigate this possibility, indentations of 300 ,m at velocities of 100 (T100) and 400 ,m/ms (T400) were applied to the tip (FT) and the proximal phalanx of digit III (PP) and the thenar eminence (Pm) of ten healthy volunteers, and compared with responses after electrical stimulation at the FT. Compound sensory action potentials (CSAPs) were recorded from the median nerve through needle electrodes at the wrist and elbow. The maximal sensory conduction velocities (SNCVs) between wrist and elbow were similar with electrical and T400 stimulation, but on average were 15% lower with T100 stimulation (P < 0.001). With both indentation velocities, SNCVs were similar regardless of stimulation sites. Amplitudes of tactile CSAPs with FT stimulation were 1,2 ,V at T400 and 0.3,0.4 ,V at T100. The CSAP areas evoked by T100 stimulation showed a reduction from fingertip to proximal finger to palm (P < 0.05,0.005), whereas those obtained with T400 stimulation showed a reduction only at the palm (P < 0.05). The results support previous studies indicating that fast indentation at 400 ,m/ms activated deeply placed Pacinian corpuscles as well as superficially situated Meissner corpuscles, whereas slower indentation at 100 ,m/ms activated primarily Meissner corpuscles. © 2001 John Wiley & Sons, Inc. Muscle Nerve 24: 1213,1218, 2001 [source] Pressure pain thresholds of upper limb peripheral nerve trunks in asymptomatic subjectsPHYSIOTHERAPY RESEARCH INTERNATIONAL, Issue 4 2000Michele Sterling Abstract Background and Purpose Palpation of peripheral nerve trunks has been advocated as a method of assessing the presence of hyperalgesic nerve tissue as a contributing factor to pain syndromes in musculoskeletal disorders of the upper quadrant. This study investigated, in the first instance, the pressure pain thresholds of the median, radial and ulnar nerve trunks of the upper limb in healthy, asymptomatic subjects. Method Forty-five male and 50 female healthy volunteer subjects participated in this study which involved measurement of pressure pain thresholds by use of pressure algometry bilaterally over the three peripheral nerve trunks in the upper limbs. Results Pressure pain thresholds were shown to be lowest in the median nerve (p=0.001) and lower in female subjects (p=0.001). Laterality (p=0.077) or the age of the subject (p=0.254) did not significantly influence results. Conclusions The study demonstrated differences in pressure pain thresholds in the three nerve trunks of the upper limb. These findings should be taken into account when interpreting the findings of nerve palpation in musculoskeletal upper quadrant disorders. Copyright © 2000 Whurr Publishers Ltd. [source] A randomized controlled trial evaluating an alternative mouse or forearm support on change in median and ulnar nerve motor latency at the wristAMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 4 2009Craig F. Conlon MD Abstract Background The purpose of this study was to determine the effects of an alternative mouse and/or a forearm support board on nerve function at the wrist among engineers. Methods This randomized controlled intervention trial followed 206 engineers for 1 year. Distal motor latency (DML) at baseline and follow-up was conducted for the median and ulnar nerves at the right wrist. Results One hundred fifty-four subjects agreed to a nerve conduction study at the beginning and end of the study period. Those who received the alternative mouse had a protective effect (OR,=,0.47, 95% CI 0.22,0.98) on change in the right ulnar DML. There was no significant effect on the median nerve DML. The forearm support board had no significant effect on the median or ulnar nerve DML. Conclusions In engineers who use a computer for more than 20 hr per week, an alternative mouse may have a protective effect for ulnar nerve function at the wrist. No protective effect of a forearm support board was found for the median nerve. Am. J. Ind. Med. 52:304,310, 2009. © 2009 Wiley-Liss, Inc. [source] 3D Computerized Model for Measuring Strain and Displacement of the Brachial Plexus Following Placement of Reverse Shoulder ProsthesisTHE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 9 2008Tom Van Hoof Abstract The aim of the present study was to develop a method for three-dimensional (3D) reconstruction of the brachial plexus to study its morphology and to calculate strain and displacement in relation to changed nerve position. The brachial plexus was finely dissected and injected with contrast medium and leaden markers were implanted into the nerves at predefined places. A reverse shoulder prosthesis was inserted in a cadaveric specimen what induced positional change in the upper limb nerves. Computed tomography (CT) was performed before and after this surgical intervention. The computer assisted image processing package Mimics® was used to reconstruct the pre- and postoperative brachial plexus in 3D. The results show that the current interactive model is a realistic and detailed representation of the specimen used, which allows 3D study of the brachial plexus in different configurations. The model estimated strains up to 15.3% and 19.3% for the lateral and the medial root of the median nerve as a consequence of placing a reverse shoulder prosthesis. Furthermore, the model succeeded in calculating the displacement of the brachial plexus by tracking each implanted lead marker. The presented brachial plexus 3D model currently can be used in vitro for cadaver biomechanical analyses of nerve movement to improve diagnosis and treatment of peripheral neuropathies. The model can also be applied to study the exact location of the plexus in unusual upper limb positions like during axillary radiation therapy and it is a potential tool to optimize the approaches of brachial plexus anesthetic blocks. Anat Rec, 291:1173-1185, 2008. © 2008 Wiley-Liss, Inc. [source] Threshold behaviour of human axons explored using subthreshold perturbations to membrane potentialTHE JOURNAL OF PHYSIOLOGY, Issue 2 2009David Burke The present study explores the threshold behaviour of human axons and the mechanisms contributing to this behaviour. The changes in excitability of cutaneous afferents in the median nerve at the wrist were recorded to a long-lasting subthreshold conditioning stimulus, with a waveform designed to maximize the contribution of currents active in the just-subthreshold region. The conditioning stimulus produced a decrease in threshold that developed over 3,5 ms following the end of the depolarization and then decayed slowly, in a pattern similar to the recovery of axonal excitability following a discharge. To ensure that the conditioning stimulus did not activate low-threshold axons, similar recordings were then made from single motor axons in the ulnar nerve at the elbow. The findings were comparable, and behaviour with the same pattern and time course could be reproduced by subthreshold stimuli in a model of the human axon. In motor axons, subthreshold depolarizing stimuli, 1 ms long, produced a similar increase in excitability, but the late hyperpolarizing deflection was less prominent. This behaviour was again reproduced by the model axon and could be explained by the passive properties of the nodal membrane and conventional Na+ and K+ currents. The modelling studies emphasized the importance of leak current through the Barrett,Barrett resistance, even in the subthreshold region, and suggested a significant contribution of K+ currents to the threshold behaviour of axons. While the gating of slow K+ channels is slow, the resultant current may not be slow if there are substantial changes in membrane potential. By extrapolation, we suggest that, when human axons discharge, nodal slow K+ currents will be activated sufficiently early to contribute to the early changes in excitability following the action potential. [source] Excitability of human muscle afferents studied using threshold tracking of the H reflexTHE JOURNAL OF PHYSIOLOGY, Issue 2 2002Cindy S.-Y. In human peripheral nerves, physiological evidence has been presented for a number of biophysical differences between cutaneous afferents and , motor axons. The differences in strength-duration properties for cutaneous afferents and motor axons in the median nerve have been attributed to greater expression of a persistent Na+ conductance (INa,P) on cutaneous afferents. However, it is unclear whether the biophysical properties of human group Ia afferents differ from those of cutaneous afferents. The present studies were undertaken to determine whether the properties of human group Ia afferents can be studied indirectly using ,threshold tracking' to measure the excitability changes in the H reflex, and to determine whether the excitability of group Ia afferents differs from that of cutaneous afferents. The strength-duration properties of the soleus H reflex and soleus motor axons were measured at rest and during sustained voluntary contractions. Similar experiments were performed on the median nerve at the wrist to study the strength-duration properties of cutaneous afferents, , motor axons and H reflex of the thenar muscles. In addition, the technique of ,latent addition' was used to determine whether there was a difference in a low-threshold conductance on soleus Ia afferent and motor axons. The present findings indicate that the strength-duration time constant (,SD) for the H reflex is longer than that for , motor axons, but similar to that for cutaneous afferents. There were no differences in ,SD for the soleus H reflex at rest and during contractions, suggesting that ,SD for the H reflex is largely unaffected by changes in synaptic or motoneurone properties. Finally, the difference in latent addition suggests that the longer ,SD of the soleus H reflex may indeed be due to greater activity of a persistent Na+ conductance on Ia afferents than on soleus , motor axons. [source] When exactly can carpal tunnel syndrome be considered work-related?ANZ JOURNAL OF SURGERY, Issue 3 2002Sonja Falkiner Background: Carpal tunnel syndrome (CTS), compression of the median nerve at the wrist, is the most frequently encountered peripheral entrapment neuropathy. Whilst rates of all other work-related conditions have declined, the number of work-related musculoskeletal disorders (which include CTS) has not changed for the past 9 years in the USA. Median days off work are also highest for CTS: 27 compared to 20 for fractures and 18 for amputations. This results in enormous Workers Compensation and other costs to the community. Awareness of CTS as a disorder associated with repeated trauma at work is now so widespread amongst workers that many have diagnosed themselves before being medically assessed, often by means of the Internet. Surprisingly, however, a definite causal relationship has not yet been established for most occupations. Although the quality of research in this area is generally poor, CTS research studies are being used as the basis for acceptance of Workers Compensation claims, substantial expensive ergonomic workplace change and even workplace closures. The fact that the incidence of work-related musculoskeletal disorders has not changed despite these latter measures would suggest that a causal relationship is not proven and that some resources are being misdirected in CTS prevention and treatment. Method: A literature review of 64 articles on CTS was conducted. This included those articles most frequently cited as demonstrating the relationship between CTS and work. Results: Primary risk factors in the development of CTS are: being a woman of menopausal age, obesity or lack of fitness, diabetes or having a family history of diabetes, osteoarthritis of the carpometacarpal joint of the thumb, smoking, and lifetime alcohol intake. In most cases, work acts as the ,last straw' in CTS causation. Conclusion: Except in the case of work that involves very cold temperatures (possibly in conjunction with load and repetition) such as butchery, work is less likely than demographic and disease-related variables to cause CTS. To label other types of work as having caused CTS, therefore, would result in inappropriate allocation of resources. It would also relieve individuals of the responsibility of addressing correctable lifestyle factors and treatable illnesses such as obesity, diabetes, smoking and increased alcohol intake which may have contributed to their CTS more that their work. This results in both avoidable long-term health effects and ongoing costs to the community. [source] Lumbrical muscle with an additional origin in the forearmANZ JOURNAL OF SURGERY, Issue 5 2001Gurmit Singh Background: Although variations in the attachments of the lumbrical muscles have been commonly reported, these have been seen mainly in the Caucasian population. The present study is the first reported case of such an anomaly in a Chinese cadaver in the literature. Methods: The upper extremities of 26 Chinese (23 male and three female) cadavers were examined. Results: Dissection of a male 66-year-old Chinese cadaver has revealed the rare case of a bipennate first lumbrical muscle with an additional origin extending from the distal part of the forearm. Its first origin arose from the flexor digitorum profundus in the hand distal to the flexor retinaculum. The intrinsic muscles in the hands of all the other cadavers were normal. Conclusions: An anomalous origin of the lumbrical from muscles in the forearm has the potential to cause compression of the median nerve in the carpal tunnel. [source] Palmaris profundus: One name, several subtypes, and a shared potential for nerve compressionCLINICAL ANATOMY, Issue 6 2009Elena Pirola Abstract The palmaris profundus is a rare, but known anatomic variation which may lead to compression of the median nerve and/or its branches. Two patients with carpal tunnel syndrome are presented in whom a palmaris profundus was discovered at operation. In these cases, median nerve compression at the wrist was attributed to the course of the extra tendon and its local mass effect on the nerve (i.e., the palmaris profundus and median nerve shared a common sheath); more commonly, the resultant decreased available space for the median nerve within the carpal tunnel due to the presence of an accessory (10th) flexor tendon is thought to be responsible. Postoperative 3 Tesla magnetic resonance imaging (MRI) was performed to demonstrate the full course of the variant muscle; despite variations in the size and longitudinal extent of the accessory musculotendinous unit, an important similarity was noted: the intimate relationship of the median nerve and the palmaris profundus. These two cases and our review of the literature highlight the fact that one name (i.e. palmaris profundus) reflects several anatomic subtypes. However, the close relationship of the palmaris profundus with the median nerve in the forearm and the palm is a common theme which emphasizes the potential pathoanatomic consequences of this relationship: nerve compression. Clin. Anat. 22:643,648, 2009. © 2009 Wiley-Liss, Inc. [source] | |||||||||||||