Anatomic variations of the median nerve within the carpal tunnel

Two hundred seventy‐five consecutive carpal tunnel releases were reviewed to identify anomalies of median nerve anatomy. High division of the median nerve was observed in nine cases; in two of these the nerve divided proximally and then rejoined distally as a “closed loop.” In 42 cases the motor branch passed through the flexor retinaculum. Multiple motor branches were present in 13 cases. The palmar cutaneous branch passed through the flexor retinaculum in seven cases. In three cases, the distal communicating sensory ramus between the medial and ulnar nerves arose proximal to the superficial arch. Median nerve anomalies within the region of the carpal tunnel are common. Knowledge of such anomalies is important to avoid iatrogenic injury.