RESUMO
AIM OF THE STUDY: The short extensor muscle of the toes (extensor digitorum brevis) is innervated by the deep peroneal nerve (DPN) but can also receive innervation from an accessory deep peroneal nerve (ADPN), a branch of the superficial peroneal nerve (SPN). PATIENTS AND METHODS: We conducted a systematic electrophysiological study of the DPN and ADPN in 200 healthy subjects (400 legs). RESULTS: We found the presence of an ADPN in 13.5% of the subjects (8.5% of the legs). On average, ADPN amplitudes and motor potential areas were one-fifth of those for the corresponding DPN. Without this systematic search, most of the ADPN would not have been detected. Comparative study of electrophysiological parameters in patients with and without ADPN showed a significantly higher (P<0.0001) DPN motor potential area ratio (distal/proximal ratio) in subjects without an ADPN. CONCLUSION: Even though electrophysiological identification of the ADPN is generally not easy (in simple DPN motor conduction studies), the nerve can sometimes be clinically symptomatic (ankle pain). Evaluation of the DPN motor potential area ratio (distal/proximal ratio) heightens the detection of ADPN.