The innervation pattern of the radial nerve at the elbow and in the forearm.

Sixty paired cadaver forearms were dissected to examine the distribution of the radial nerve branches to the muscles at the elbow and forearm. Emphasis was placed on the innervation of the extensor carpi radialis brevis and the supinator muscles because of discrepancies in the literature concerning these muscles. The most common branching pattern (from proximal to distal) was to brachioradialis, extensor carpi radialis longus, superficial sensory, extensor carpi radialis brevis, supinator, extensor digitorum/extensor carpi ulnaris, extensor digiti minimi, abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus and extensor indicis. The branch to extensor digitorum and extensor carpi ulnaris came off as a common stem often with the branch to extensor digiti minimi. The branch to the ECRB muscle was noted to arise from the posterior interosseous nerve in 45%, superficial sensory nerve in 25% and at the bifurcation of the posterior interosseous and superficial sensory nerves in 30% of specimens. The supinator had an average of 2.3 branches from the posterior interosseous nerve (range 1-6). The branches to the supinator showed a wide variability proximal to and within the supinator.