Ulnar nerve compression by an anomalous muscle following carpal tunnel release: A case report

We describe the acute development of ulnar nerve compression following carp al tunnel release in a patient with an accessory palmaris longus muscle. Al though anomalous muscles in the wrist are relatively common and may produce ulnar nerve compression, this particular occurrence following carpal tunne l release has not been previously described in the literature. We theorize that the compression of the ulnar nerve proximal to Guyon's canal was cause d by increased tension along the long axis of the anomalous accessory palma ris longus muscle as a consequence of transverse carpal ligament division. (J Hand Surg 2000;25A:740-744. Copyright (C) 2000 by the American Society f or Surgery of the Hand).