Bilateral flexor carpi radialis brevis and unilateral flexor carpi ulnaris brevis muscle: case report.

We present findings of anomalous musculotendinous anatomy in a patient having exploration of an acute volar wrist laceration. Surgical dissection demonstrated supernumerary flexor carpi radialis brevis and flexor carpi ulnaris brevis muscle bellies crossing the radiocarpal and ulnocarpal joints, in addition to injuries to several normal tendons and nerves. Postoperative magnetic resonance imaging confirmed the presence of a bilateral supernumerary flexor carpi radialis brevis but contralateral absence of flexor carpi ulnaris brevis.