3Roots Anterior rami of C5 to C8, and most of T1 Gray rami communicantes from the sympathetic trunk:postganglionic sympathetic fibers
4Trunks The superior trunk : The middle trunk : The inferior trunk C5 and C6 roots;The middle trunk :C7 root;The inferior trunkC8 and T1 roots.
5Divisions & Cords Divisions Cords Anterior and a posterior divisionThe three anterior divisions : anterior compartments of the arm and forearm;The three posterior divisions: the posterior compartments.CordsLateral cordMedial cordPosterior cord
6Dorsal scapular Originates from the C5 root Pierce the middle scalene muscleInnervates the rhomboid major and minor muscles
7Long thoracic Originates from C5 to C7; Down the axilla to supply the serratus anterior muscleLies on the superficial aspect of muscle
14Medial cord The medial pectoral nerve major muscle. The medial cutaneous nerve of arm (medial brachial cutaneous nerve)The medial cutaneous nerve of forearm (medial antebrachial cutaneous nerve)The medial root of median nerveThe ulnar nerve
20Radial nerveAll muscles in the posterior compartments of the arm and forearm;The skin on the posterior aspect of the arm and forearm, the lower lateral surface of the arm,The dorsal lateral surface of the hand.
36Ulnar nerve Ulnar nerve Muscular branches Two small cutaneous branches Palmar branch supply skin on the medial side of the palm;The larger dorsal branchPosterior surfaces of the medial one and one-half digits.Ulnar nerve