Somatosensory evoked potentials from musculocutaneous nerve in the diagnosis of brachial plexus injuries.

A technique for recording somatosensory evoked potentials using stimulation of musculocutaneous sensory nerve fibers proximal to the wrist has been used in 10 normal subjects and in 8 patients with traumatic lesions of proximal parts of the brachial plexus. The technique gave satisfactory evoked potentials in all normal subjects and provided useful information in patients with avulsion of the 5th and 6th cervical roots. The results were similar to those obtained by radial nerve stimulation. The results in 3 patients with upper trunk injuries and in 1 patient with avulsion of the 5th cervical root were unhelpful. In 2 patients with multiple cervical root avulsions the evoked potentials from cervical cord and contralateral scalp were absent and were attenuated at Erb's point. This is the first report where musculocutaneous nerve evoked potentials have been applied to a group of patients.