Anatomical variations in the ulnar nerve and hypothenar muscles

Trifurcation of the ulnar nerve proximal to Guyon’s canal was seen in the left hand of a cadaver. The nerve divided into deep and superficial divisions and a separate muscular branch that supplied three heads for the abductor digiti minimi. An unusual loop of the dorsal cutaneous branch of the ulnar nerve communicated with this muscular branch and with the digital sensory branches of the superficial division of the ulnar nerve. The connection to the muscular branch is novel and has not been described previously. The abductor digiti minimi had three overlapping heads. The median nerve above the flexor retinaculum appeared on the ulnar side of a radially positioned palmaris longus tendon. These combinations of neuromuscular variations are essential knowledge that should be made available to surgeons and practitioners.