Carpal Tunnel Syndrome Secondary to an Accessory Flexor Digitorum Superficialis Muscle Belly: Case Report and Review of the Literature

The description is given of an anomalous muscle arising from the flexor digitorum superficialis indicis tendon distal to the transverse carpal ligament which presented as carpal tunnel syndrome.

A 23 year old female nurse developed acute sensory symptoms of median nerve compression. Early exploration revealed abnormal flexor superficialis indicis muscle as the compressing structure. Symptoms were relieved by freeing the muscle from the nerve.