Carpal Tunnel Syndrome Caused by Anatomic Anomalies Muscles: A Three Cases Report

Carpal tunnel syndrome (CTS) is the most frequent peripheral compression neuropathy. Anatomic variations may be encountered during carpal tunnel surgery.1–3 Compression of the median nerve at the wrist is frequently encountered. Carpal tunnel syndrome usually occurs without any obvious extrinsic causes; several cases have however been reported caused by anomalous or hypertrophic muscles. A survey of the literature shows that compression neuropathy of the median nerve has been reported in relation with anomalies affecting three muscles: the first (or second) lumbrical, the palmaris longus and its anatomic variants and the superficial flexor of long fingers. We can suspect the presence of such an anomalous muscle when the compression syndrome concerns a patient who is not within the “usual” age group with symptoms initiated or aggravated by physical exercise.

This report presents three cases of carpal tunnel syndrome caused by anatomic anomalousmuscles diagnosed peroperatively.