Ulnar Nerve Innervation to Triceps: A Cadaveric Study and a Technical Note on Partial Triceps to Biceps Transfer

BACKGROUND: The loss of elbow flexion is a routinely encountered problem in clinical practice. There is no literature on ulnar nerve innervation to triceps in addition to the radial nerve which is dual nerve innervation to triceps in the Indian population. We intend to study the incidence of ulnar nerve innervation to the medial head of triceps in Indian population and also the clinical feasibility of transfer of long and medial head of triceps tendon to biceps around the medial aspect of humerus. MATERIALS AND METHODS: A cross-sectional study was conducted using 32 fresh-frozen skeletally mature cadavers of Indian origin. The possible contribution of the ulnar nerve to medial head of triceps in addition to the radial nerve was recorded. The arm length, the distance where the ulnar nerve pierces the medial intermuscular septum from medial epicondyle; the distance of the ulnar nerve fascicle from the medial epicondyle was also measured. RESULTS: The incidence of ulnar nerve innervation to the medial head of triceps was 43.8%. Mean arm length was 29.13 cm. Mean distance where the ulnar nerve pierced the medial intermuscular septum from medial epicondyle was 9.93 cm. Mean distance of the ulnar nerve branch to the triceps from medial epicondyle was 8.01 cm. CONCLUSION: This study reveals the presence of dual nerve innervation to triceps in 43.8% of the Indian population. The clinical implication would be to look for the possible contribution of the ulnar nerve fascicle to the medial head of triceps, which will help us to include the medial head along with the long head of triceps while performing partial triceps-to-biceps tendon transfer, and the other use would be as a donor fascicle when performing a nerve transfer.