A case of cubital tunnel syndrome caused by the snapping of the medial head of the triceps brachii muscle.

A rare case of cubital tunnel syndrome caused by the snapping of the medial head of the triceps brachii muscle in a 20-year-old man was reported. The ulnar nerve was compressed by the medial head of the triceps, which snapped from the back, and was constricted at the tendinous arch of origin of the flexor carpi ulnaris. Medial epicondylectomy with division of tendinous arch was carried out, and the postoperative course was satisfactory. Our case is compared with four cases reported previously.