The palmaris brevis profundus. An anomalous muscle associated with ulnar nerve compression at the wrist.

An anomalous muscle is uncommonly associated with ulnar nerve compression at the wrist. Anomalies of the palmaris longus, abductor digiti minimi, flexor digiti minimi, and flexor carpi ulnaris have been described. Another case is presented in which the anomalous muscle would appear to be a duplication of the palmaris brevis. This muscle has been named the "palmaris brevis profundus."