Nerve · Shoulders

Musculocutaneous nerve

Nervus musculocutaneus

The musculocutaneous nerve is named for what it does in two halves: first muscular, then cutaneous. It supplies the three muscles of the front of the arm — coracobrachialis, biceps brachii and brachialis — which bend the elbow and turn the palm up, and then, having run out of muscles, it emerges at the side of the biceps tendon and continues purely as a skin nerve down the outer edge of the forearm. Weakness of elbow flexion combined with a numb strip along the thumb side of the forearm points here.