Carpal tunnel syndrome secondary to an accessory flexor digitorum superficialis muscle belly: case report and review of the literature.

Anomalous muscles usually do not cause symptoms but are of academic interest mainly discovered during cadaveric dissection. An aberrant muscle belly arising from the index finger flexor digitorum superficialis tendon causing carpal tunnel syndrome is rare. The management of such an anatomical variant is dependent on whether the median nerve compression is associated with a palpable mass. A brief case highlighting important management principles along with a complete literature review is reported.