Bifid median nerve variations: A cadaveric study

Abstract

Bifid median nerve (BMN) is an anatomical variation that occurs when the main median nerve trunk splits into medial and lateral trunks prior to entering the hand within the carpal tunnel (CT). The classification of BMN can be further divided into subcategories, which are based on associated abnormalities and location of branching. In this study, the upper extremities of twenty‐nine cadaveric specimens were examined for the presence of BMN in the flexor forearm and hand regions (14 females, 15 males). Of the 58 upper extremities examined, 6 exhibited BMN patterns (10.3%; 4 female, 2 male), with both trunks traveling within the CT into the hand. Two distinct bifid branching patterns were also observed: (B1) mid‐forearm, proximal to carpal tunnel (n=2 females) and (B2) wrist level, within CT (n=2 females, 2 males). In both B1 cases, the smaller medial trunk pierced the flexor digitorum superficialis muscle, traveled within the CT with the larger lateral trunk, and gave off communicating branches to both the lateral trunk and superficial branch of the ulnar nerve after entering the left hand. Incidence of BMN was found to be higher in female cadavers (67%), and in left upper extremities (67%). Knowledge of variable median nerve branching patterns, especially as it is associated with the CT, is important for diagnostic and surgical interventions.Grant Funding Source: n/a