The musculocutaneous nerve provides: motor innervation to all muscles in the anterior compartment of the arm, and sensory innervation to skin on the lateral surface of the forearm.
The median nerve enters the arm from the axilla at the inferior margin of the teres major muscle (Fig. 7.68). It passes vertically down the medial side of the arm in the anterior compartment and is related to the brachial artery throughout its course: