Electromyographic study of the extensor apparatus of the forearm

Abstract

Abstract An electromyographic study of the extensor apparatus of the forearm, using a multichannel electromyograph and bipolar needle electrodes, was carried out on 12 subjects. Recordings were obtained concurrently from medial, lateral and long heads of the triceps brachii and anconeus. The investigation confirms that the three heads contract independently during extension of the forearm, that the medial head and the anconeus are always active, and that the lateral head and, to a lesser extent, the long head act as reinforcing auxiliaries. The anconeus was found to be active also during resisted but not free loaded pronation and supination, contrary to commonly held opinion.