IT HAS BEEN our experience, during the determination of peroneal nerve conduction velocities in some patients, that the amplitude of the evoked response, as recorded by surface electrodes over the extensor digitorum brevis muscle, is larger when this nerve is stimulated at the knee than when stimulated at the ankle (Fig 1). In these patients stimulation behind the lateral malleolus elicited an additional response (Fig 1). This suggested the existence of an anomalous branch of the nerve to this muscle. Because we could not find a description of this electrical phenomenon in the literature, we determined to study its incidence in normal subjects and in patients. The following is an account of our findings.
Materials and Methods
Two groups of subjects were tested. The first group consisted of 22 healthy subjects and 82 patients referred to the electromyographic laboratory with a diversity of neurological complaints. The ages ranged from