Case: A 20-year-old right hand dominant woman presented with an audible and painful snapping wrist occurring with finger flexion. This bothersome mechanical finding and concomitant carpal tunnel syndrome (CTS) did not resolve with conservative measures. Dynamic magnetic resonance imaging revealed anomalous flexor digitorum profundus (FDP) muscle bellies as the cause of the mechanical snapping and irritation of the median nerve. Carpal tunnel release and excision of anomalous muscle within the carpal tunnel and distal forearm provided complete resolution of symptoms.
Conclusion: Anomalous muscle bellies of the FDP is a rare cause of a volar snapping wrist and CTS.
Copyright © 2021 by The Journal of Bone and Joint Surgery, Incorporated.