Brachial Plexus Anatomy

I would draw the five levels from medial to lateral: roots, trunks, divisions, cords and branches - 'Randy Travis Drinks Cold Beer'. The roots are the anterior rami of C5 to T1; from the roots come the dorsal scapular nerve (C5) and the long thoracic nerve (C5-7). The roots form three trunks - upper (C5-6), middle (C7) and lower (C8-T1) - and from the upper trunk come the suprascapular nerve and the nerve to subclavius. Each trunk splits into anterior and posterior divisions behind the clavicle. The divisions form three cords named by their relation to the axillary artery: lateral, posterior and medial. The lateral cord gives the lateral pectoral nerve, musculocutaneous nerve and the lateral root of the median; the posterior cord gives 'ULTRA' - upper subscapular, lower subscapular, thoracodorsal, radial and axillary; the medial cord gives the medial pectoral nerve, the medial cutaneous nerves of arm and forearm, the ulnar nerve and the medial root of the median. The five terminal branches are the musculocutaneous, axillary, radial, median and ulnar nerves.