The innervation of the medial humeral epicondyle: implications for medial epicondylar pain

The purpose of this study was identification of the innervation of the medial humeral epicondyle which has not been described before. In 20 patients, the medial intermuscular septum was evaluated histopathologically: the nerve was identified in 15 specimens without S-100 staining, and in the remaining 5 with S-100 staining. In six fresh cadavers, bilateral dissections identified the source of this nerve as the radial nerve in the axilla, coursing adjacent to the ulnar nerve in the upper arm, then moving laterally to be superficial to, or within, the medial intermuscular septum, until the nerve terminated in the periosteum of the medial humeral epicondyle, at the origin of the flexor-pronator muscle mass. In one specimen, a branch from the ulnar nerve in the axilla contributed to this nerve to the medial humeral epicondyle.