Dual Anatomic Variations in the Median Nerve: Adding Layers of Complexity for Carpal Tunnel Release

Abstract

Anatomical variations in the median nerve have been extensively documented since the inception of carpal tunnel surgery. We report a dual anatomic variation in the median nerve encountered during the carpal tunnel decompression. The bifid median nerve was associated with preligamentous thenar motor branch arising from the ventral aspect of the radial portion of the median nerve, remaining deep to antebrachial fascia and then piercing the transverse carpal ligament to reach the thenar muscles. Lanz described the various anomalies of the median nerve in the carpal tunnel and classified the bifid median nerve as group III. Various abnormalities associated with the bifid median nerve are further classified by Al-Qattan et al and classified the bifid median nerve associated with aberrant nerve branches as group VI.