Closed traumatism of the musculocutaneous nerve

Isolated palsy of the musculocutaneous nerve, terminal branch of the latera l cord of the brachial plexus, is rare. It is responsible for sensory loss of the distal forearm and weakness of elbow flexion. It occurs after should er or clavicle surgery, trauma (fracture, dislocation, blows on the shoulde r), violent exercice or extension of the forearm, prolonged positioning of the shoulder in extension-abduction-external rotation and phlebotomy. Diffe rent mechanisms such as stretching, compression or direct nerve injury are encountered. We report 5 cases with isolated musculocutaneous nerve palsy, including bilateral palsy caused by violent forearm extension. In other cas es, mechanisms were an extensive stretching during surgery and compression caused by prolonged supine position. Different injury locations and causes described in literature are reviewed.