Proximal median neuropathies: electromyographic and clinical correlation

Results of electrophysiologic and clinical findings in 17 patients with proximal median neuropathy were reviewed. The cause of neuropathy was trauma in 5 patients, overuse of the pronator teres in 3 patients, postinfectious in 2 patients, secondary to a congenital lesion in 1 patient, and undetermined in 6 patients. The neuropathy involved the main branch of the median nerve at or proximal to the pronator teres muscle (high median neuropathy) in 14 patients, and the anterior interosseous portion of the nerve in 3 patients. Electrophysiologic findings, especially needle electromyography (EMG), were more definitive than findings expected from clinical examinations. EMG and operative findings demonstrated that median nerve compression by the pronator teres produces denervation of this muscle as well as distal muscles. EMG cannot differentiate a median nerve lesion at the pronator teres from a more proximal lesion. Follow-up data were available in 7 of 10 nonsurgically managed patients, and in 6 of 7 patients with surgical decompression. Six patients in each group were either improved or normal.