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

A major component of the axilla are the cords (fasciculi) and branches (rami) of the plexus brachialis, a major network of nerves supplying the upper limb (membrum superius). The n. pectoralis lateralis arises from the fasciculus lateralis plexus brachialis and primarily innervates the m. pectoralis major (fibers may also pass to the n. pectoralis medialis via the ansa pectoralis, when present). The n. musculocutaneus is a terminal branch of the fasciculus lateralis which provides motor innervation to the muscles of the anterior arm (namely the m. biceps brachii, m. coracobrachialis and m. brachialis) as well as sensory innervation of the lateral forearm. The n. medianus arises from radices mediales and laterales; it is branchless within the arm . Branches of the fasciculus medialis plexus brachialis include the n. pectoralis medialis (which provides motor innervation to the m. pectoralis minor and pars sternocostalis musculi pectoralis majoris), n. cutaneus medialis brachii (provides sensory innervation to the skin of the medial aspect of the arm) and n. cutaneus medialis antebrachii providing sensory innervation to the skin of the arm (brachium) overlying the m. biceps brachii and medial forearm (antebrachium).