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At least 19 recordsLinked to original sources
PubMed1979

Lipofibroma of the median nerve.

Tumors arising within the median nerve in the region of the distal forearm, wrist, and palm are rare and their exact pathological nature has not been well clarified. One case is reported in a 47-year-old woman, in whom a mass of 3 years' duration was located in the thenar eminence of the right hand without causing any sensory or motor deficit. The tumor was surgically excised, and the continuity of the nerve branches was preserved. The diagnosis of lipofibroma of the median nerve is recommended for this entity. Other pathological lesions of the median nerve are mentioned.

Female↗
PubMed1979

Syndromes of compression of the median nerve in the proximal forearm (pronator teres syndrome; anterior interosseous nerve syndrome).

Entrapment of the median nerve in the proximal forearm is seen in two forms: the pronator teres syndrome, and the anterior interosseous nerve (or Kiloh-Nevin) syndrome. Both syndromes are rare, and they comprised approximately 1% of the compression syndromes of the upper limb which were treated operatively by the authors. The symptoms, signs, etiologies, and intraoperative findings are discussed. It is pointed out that certain of the clinical features may resemble those of irritation of the median nerve by a supracondylar process or Struthers' ligament. Although both proximal median entrapment syndromes have a favorable prognosis when treated non-operatively, the authors recommend operative treatment in cases in which there is no perceptible improvement following 8 weeks of non-operative treatment, since this is likely to speed and enhance recovery. Nine cases of the pronator teres syndrome (8 treated successfully by operation, 1 failure) and 2 cases of the anterior interosseous nerve syndrome (both fully recovered) are added to the cases reported previously in the literature.

Adult↗
PubMed1979

Lipofibroma of the median nerve in the palm and digits of the hand.

Lipofibroma of the median nerve or its cutaneous branches is a rare benign tumor. The diagnosis is usually made at surgical exploration of a mass in the distal part of the forearm, the wrist, the palm, or the digits of the hand, which may be asymptomatic or associated with symptoms of carpal-tunnel syndrome. The diagnosis should be made when exploration reveals fusiform enlargement of a segment of the median nerve or its cutaneous branches without hypertrophy of the regional tissues. The tumor is limited to within the epineurial sheath, which is intact, shiny, orange-yellow, firm, thick, and non-resilient to dissection. The nerve tumor does not infiltrate the surrounding tissues nor do the surrounding tissues infiltrate the nerve. If the epineurium is opened, the nerve fibers are found to be inseparably infiltrated by fibrous and fatty tissues. Histologically, these are of epineurial, perineurial, and endoneurial origin. A forzen-section biopsy of a palmar cutaneous branch is suggested to confirm the diagnosis. Once the diagnosis is confirmed, the treatment should be limited to release of the fascia over the involved nerve. The tumorous part of the median nerve was partly or completely excised in seven of twenty-six cases reviewed in the literature and this report. It is to emphasize a conservative approach when such a tumor of the median nerve is encountered at surgery that we describe two more cases.

Adolescent↗
PubMed1979

[The pronator teres syndrome. Clinical aspects, pathogenesis and therapy of a non-traumatic median nerve compression syndrome in the space of the elbow joint].

The proximal compression neuropathy of the median nerve is described by 11 personal cases and a review of literature. The most reliable diagnostic sign is "pronation-pain", discomfort in the forearm localised under the pronator teres, produced by passive supination of the wrist, by active pronation from this position against resistance, okr by local pressure. A nearly constant finding is weakness of grip and paraesthesia or hypaesthesia of the fingers, not always following the normal median nerve distribution. Three different anatomic points of possible compression are described: 1. The supracondylar process of the humerus, or Struthers' ligament, a rare compression mechanism. 2. The passing of the nerve through the two variable heads of the pronator teres muscle. 3. The sharp edged superficialis bridge. Apart from compression of the entire median nerve single branches of the median nerve can be entrapped seperately (the anterior interosseus nerve, the Martin-Gruber-anastomosis to the ulnar nerve) Conservative treatment with immobilisation and local electric interference current application may be satisfactory. If clinical improvement is insufficient, surgical decompression is indicated.

Adolescent↗
PubMed1979

Evaluation of equine radial and median nerve conduction velocities.

Eleven ponies and 13 horses were used to develop a technique for determining conduction velocity for the radial and median nerves and establishing normal limits for these values. One pony was euthanatized to determine the course of the radial and the median nerves. From this dissection, both proximal and distal stimulation sites for the radial and the median nerves were selected, as well as areas for recording muscle evoked responses from the abductor digiti I longus (extensor carpi obliquus) and the radial head of the deep digital flexor muscles. The other ten ponies and the horses were used in studies on the stimulation of the nerves and recording of muscle evoked responses from which conduction velocity could be calculated. Conduction velocities for the radial and the median nerves were calculated and recorded.

Animals↗
PubMed1979

Funicular localization in partial median nerve injury at the wrists.

The funiculi of the median nerve at the wrist carrying the motor and sensory fibers innervating the hand were described in 1945 by Sunderland after an extensive anatomic study. In an attempt to confirm clinically the findings of that study, 7 patients with partial median nerve laceration at the wrist are presented. The findings in these patients support the schema developed from Sunderland's study except for the funiculi subserving the 1st and 2nd lumbricals which appear to be more dorsally placed. They also tend to confirm Sunderland's finding that the mixing of nerve fibers from different funiculi and the formation of intraneural plexuses occur more proximal than at the levels of injuries in the patients studied.

Adult↗
PubMed1978

A teased-fibre study of the median nerves of vitamin B12-depleted baboons.

Isolated nerve fibres of the median nerve of normal baboons and baboons kept on diets deficient in vitamin B12, and supplemented with potassium cyanide and potassium thiocyanate injections, were examined by the teased-fibre technique. Regression lines of internodal length on fibre diameter were obtained. Small differences between the groups were apparent but were of uncertain significance. There was occasional evidence of segmental demyelination and Wallerian degeneration but this was not characteristic of any particular group.

Animals↗
PubMed1977

Experimental sensory reinnervation of the median nerve by nerve transfer in monkeys.

Anastomosis of the superficial radial nerve, the dorsal cutaneous branch of the ulnar nerve, or both to the distal cut end of a widely resected median nerve in monkeys was followed by successful sensory reinnervation of the thumb, index finger, and long finger within thiry-five to forty weeks. Success was ascertained by the presence of an intact anastomosis as observed grossly without any evidence of spontaneous regeneration of the median nerve. Reinnervation was confirmed by histological and histochemical reactions observed in the Meissner's corpuscles in the skin innervated by the median nerve. The demonstration of nerve fiber and the presence of normal specific and non-specific cholinesterase reactions exhibited by the Meissner's corpuscles in the cholinesterase preparations were considered the histological criteria for successful reinnervation. These histological and histochemical observations may explain the reported functional sensory recovery in clinical cases when similar nerve transfers were done.

Animals↗
PubMed1979

The carpal tunnel syndrome: localization of conduction abnormalities within the distal segment of the median nerve.

Palmar stimulation was used to assess median nerve conduction across the carpal tunnel in 61 control patients and 105 patients with the carpal tunnel syndrome. With serial stimulation from midpalm to distal forearm the sensory axons normally showed a predictable latency change of 0.16 to 0.21 ms/cm as the stimulus site was moved proximally in 1 cm increments. In 47 (52 per cent) of 91 affected nerves tested serially, there was a sharply localized latency increase across a 1 cm segment, most commonly 2 to 4 cm distally to the origin of the transverse carpal ligament. In these hands, the focal latency change across the affected 1 cm segment (mean +/- SD: 0.80 +/- 0.22 ms/cm) averaged more than four times that of the adjoining distal (0.19 +/- 0.09 ms/cm) or proximal 1 cm segments (0.19 +/- 0.08 ms/cm). In the remaining 44 (48 per cent) hands, the latency increase was distributed more evenly across the carpal tunnel. Unlike the sensory axons the motor axons were difficult to test serially because of the recurrent course of the thenar nerve, which may be contained in a separate tunnel. The wrist-to-palm latency was significantly greater in the patients with carpal tunnel syndromes than in the controls for sensory (2.18 +/- 0.48 ms v 1.41 +/- 0.18 ms) and motor axons (2.79 +/- 0.93 ms v 1.50 +/- 0.21 ms). Consequently, there was considerable difference between the carpal tunnel syndromes and controls in SNCV (38.5 +/- 7.5 m/s v 57.3 +/- 6.9 m/s), and MNCV (28.2 +/- 4.5 m/s v 49.0 +/- 5.7 m/s). In the remaining distal segment, however, there was only a small difference between the two groups in sensory (1.48 +/- 0.28 ms v 1.41 +/- 0.22 ms) and motor latency (2.15 +/- 0.34 ms v 2.10 +/- 0.31 ms). The exclusion of the relatively normal distal latency made it possible to demonstrate mild slowing across the carpal tunnel in 36 (21 per cent) sensory and 40 (23 per cent) motor axons of 172 affected nerves when the conventional terminal latencies were normal. Sensory or motor conduction abnormalities were found in all but 13 (8 per cent) hands. Without palmar stimulation, however, an additional 32 (19 per cent) hands would have been regarded as normal.

Adolescent↗
PubMed1975

Analysis of motor conduction velocity in the human median nerve by computer simulation of compound muscle action potentials.

A digital computer was used to reconstruct compound muscle action potentials recorded from the human thenar eminence after stimulation of the median nerve. The programme allowed the following parameters to be varied: (1) the dimensions of a representative single motor unit potential; (2) the number of motor units in the muscle and the range and distribution of conduction velocities in their nerve fibres; and (3) the distance along the nerve from the point of stimulation to the muscle. The reconstructed compound muscle action potentials were similar to real compound potentials recorded from normal subjects. The number of single motor units and the range of conduction velocities required for the reconstruction correlated with quantitative histologic studies of the recurrent branch of the median nerve to the thenar muscles. By altering the distribution of conduction velocities it was possible to study the effect of abnormal patterns of nerve conduction on the configuration of the simulated compound muscle action potentials. It was found that abnormally slow conduction caused an increased discrepancy between the main parameters of compound potentials corresponding to stimulation of the nerve at proximal and distal sites. These observations suggest that a careful analysis of the differences between pairs of compound muscle action potentials may provide a method for more detailed assessment of conduction velocity in clinical studies of peripheral nerve disorders.

Action Potentials↗
PubMed1978

Peripheral median nerve damage secondary to brachial arterial blood gas sampling.

Examination at 18 months post-term of 139 infants of birth weight less than or equal to 1,500 gm revealed 18 instances (13%) of persistent median nerve damage. All affected infants had received frequent percutaneous brachial artery punctures as neonates. Block sections of the cubital fossa done at autopsy on 12 randomly selected very low-birth-weight infants showed perineural hemorrhage, and Wallerian degeneration or traumatic neuroma of the median nerve in eight patients. It is recommended that brachial artery punctures be avoided whenever possible in the neonatal period.

Autopsy↗
PubMed1979

Right/left differences of median nerve evoked scalp potentials in multiple sclerosis.

Scalp potentials evoked by electrical stimulation of the median nerve at the wrist were examined in multiple sclerosis patients and healthy controls. The latencies of the first negative peak (about 18 ms latency) of the response to right and to left-sided stimulation were compared. Forty-eight of 60 measured latency differences in 15 suspected or certain MS patients were more than 3 standard deviations beyond the average difference in controls (arbitrary norm limit), whereas none of the 56 results of the 14 controls was in that range. Fifteen of 24 latency differences in 6 patients without anamnestic or clinical sensory disturbances in the arms were above the limit. On the other hand, conduction velocity between wrist, neck and scalp did not differentiate controls from patients. We suggest using latency differences of the early components of right and left median nerve-evoked scalp potentials as a mean for the early detection of functional disturbances in multiple sclerosis.

Adult↗
PubMed1978

Somatosensory-evoked potentials elecited by bilateral stimulation of the median nerve and its clinical application.

Somatosensory evoked potentials (SEPs) elicited by bilaterally simultaneous median nerve stimulation (BS) were studied in 28 normal subjects and in 20 patients with various cerebral lesions. In normals, SEP'S evoked by BS were symmetric between the homologous areas of the two hemispheres and resembled the response contralateral to unilateral stimulation (US). In patients with a cerebral lesion, BS responses were not only asymmetric but often differed in wave form from the response of the affected hemisphere to contralateral US. These alterations were attributed to the cumulative interactions of the anomalous contralateral and ipsilateral components. The additional use of BS made it possible to demonstrate SEP abnormalities that might have been regarded as normal or equivocal if only the US method had been used. The neurophysiologic mechanisms of the origin of SEP are discussed.

Adult↗
PubMed1977

Median nerve compression and trigger finger in the mucopolysaccharidoses and related diseases.

Patients with Hurler's syndrome (MPS-1H), I-cell disease (ML-II) and pseudo-Hurler's syndrome (ML-III) had median nerve compression and triggering of the fingers which limited finger extension. To our knowledge, this combination has not been reported previously in patients with mucopolysaccharidoses and related disorders. In all of our 3 cases the median nerve was compressed by thickened flexor tenosynovium. Synovectomy and resection of the volar carpal ligament improved the hand function in all, including the mentally retarded patient with Hurler's syndrome. Release of the fibroosseous tunnel in two patients was followed by an increased range of motion (but not full extension). A fourth patient, without a mucopolysaccharide storage disorder, also had the combination of trigger finger and carpal tunnel syndrome.

Carpal Tunnel Syndrome↗
PubMed1979

Resection of the median nerve without sequelae (resection of 15 cm due to neurofibroma).

A case of neurofibroma of the median nerve at the wrist is reported. An operation to resect 15 cm of the nerve was performed; no transplant was substituted. No motor or sensory paralysis was noted, either directly after the operation or at follow up after nine years. Injection of procaine into the ulnar nerve at the epitrochlear groove demonstrated complete compensation, by means of anastomoses between the two nerves at the upper third of the forearm. It is assumed that the type of lesion (circumscribed neurofibromatosis) beginning in infancy or childhood, had some influence in giving rise to this substitution.

Adult↗
PubMed1979

Spinal evoked potential (SEP) obtained by stimulation on the median nerve--experimental and clinical studies.

The present study was done experimentally and clinically to measure the segmental spinal evoked potential (SEP) of the cervical cord, stimulated on the median nerve, to try to determine the location and severity of cord lesion in patients with cervical spondylotic myelopathy. SEP in control subjects consisted of two waves. The primary reactive wave (R wave) consists of both the nerve root potential and the funiculus posterior potential. The secondary reactive wave (N wave) consists of the post-synaptic potential in the spinal cord. With regard to cervical spondylotic myelopathy, in the early stages the N-wave weakens or disappears at the level of lesion, then, as damage progresses, the R-wave also weakens or disappears.

Adult↗
PubMed1977

Short latency potentials recorded from the neck and scalp following median nerve stimulation in man.

Short latency evoked potentials were recorded from sites overlying the cervical and thoracic vertebrae, the clavicles, mastoid processes and cerebral cortex, following percutaneous stimulation of median nerve fibres at the elbow, wrist and fingers in 23 normal subjects. At least four major early components each with simultaneous positive and negative constituents, plus the first component (N20) of the cortical response, were all found to be mediated by sensory afferent fibres with conduction velocity 65--75 m/sec in the forearm of one subject. Study of the distribution of these potentials, using reference electrodes located at Fz or over the lower part of the spine, has led to the proposal of generator sites in the brachial plexus (N9), spinal roots or dorsal columns (N11), spinal grey matter or brain stem (N13), and brain stem or thalamus (N14). Comparison with intrathecal recordings in man lends support to the view that N11 and N13 are generated in or adjacent to the spinal cord. It is hoped the findings may extend the clinical applications of a non-invasive technique for investigating the afferent sensory pathways in man.

Adult↗