Nerves of the arm and the shoulder - Anterior view (English)

A major component of the axilla are the cords and branches of the brachial plexus, a major network of nerves supplying the upper limb. The lateral pectoral nerve arises from the lateral cord of brachial plexus and primarily innervates the pectoralis major muscle (fibers may also pass to the medial pectoral nerve via the ansa pectoralis, when present). The musculocutaneous nerve is a terminal branch of the lateral cord which provides motor innervation to the muscles of the anterior arm (namely the biceps brachii, coracobrachialis and brachialis muscles) as well as sensory innervation of the lateral forearm. The median nerve arises from medial and lateral roots; it is branchless within the arm. Branches of the medial cord of the brachial plexus include the medial pectoral nerve (which provides motor innervation to the pectoralis minor and sternocostal head of the pectoralis major muscle), medial brachial cutaneous nerve (provides sensory innervation to the skin of the medial aspect of the arm) and medial antebrachial cutaneous nerve providing sensory innervation to the skin of the arm overlying the biceps brachii and medial forearm.