The role of the musculocutaneous and radial nerves in elbow flexion and forearm supination: a biomechanical study.

The intention of this prospective study was to evaluate the role of the musculocutaneous and radial nerves in elbow flexion and forearm supination. The study included 29 patients having loco-regional anaesthesia for minor hand surgery. Elbow flexion and forearm supination forces were evaluated before and after an isolated musculocutaneous nerve block in one group and an isolated radial nerve block in another group. The results showed that the biceps tendon is responsible for 47% of the forearm supination force and the combination of brachioradialis and the supinator for 64% of this force. It showed also that the musculocutaneous and radial nerves contribute by 42% and 27.5%, respectively, to the flexion force of the elbow. These results are intended to help surgeons in decision making when treating chronic biceps tendon rupture, in repair of traumatic brachial plexus neuropathy and in using tendon transfers, such as the Steindler transfer, around the elbow.