Origin - terminal branch of lateral cord, receiving fibers from C5-C7

course - exits axilla by piercing coracobrachialis; descends between biceps brachii and brachialis, supplying both; continues as lateral cutaneous nerve of forearm

structures innervated - muscles of anterior compartment of arm (coracobrachialis, biceps brachii and brachialis): skin of lateral aspect of forearm

Origin - lateral root of median nerve is a terminal branch of lateral cord (C6,C7 fibers); medial root of median nerve is a terminal branch of medial cord (C8,T1 fibers)

course - lateral and medial roots merge to form median nerve lateral to axillary artery; descends through arm adjacent to brachial artery, with nerve gradually crossing anterior to artery to lie medial to artery in cubital fossa

structures innervated - muscles of anterior forearm compartment (except for flexor carpi ulnaris and ulnar half of flexor digitorum profundus), five intrinsic muscles in thenar half of palm and palmar skin

origin - larger terminal branch of medial cord, receiving fibers from C8, T1, and often C7

course - descends medial arm; passes posterior to medial epicondyle of humerus; then descends ulnar aspect of forearm to hand

structures innervated - flexor carpi ulnaris and ulnar half of flexor digitorum profunds (forearm); most intrinsic muscles of hand; skin of hand medial to axial line of digit 4

origin - side branch of lateral cord, receiving fibers from C5, C6 (primarily), C7

course - pierces costocoracoid membrane to reach deep surface of pectoral muscles; a communicating branch to the medial pectoral nerve passes anterior to axillary artery and vein

structures innervated - primarily pectoralis major; but some lateral pectoral nerve fibers pass to pectoralis minor via branch to medial pectoral nerve

origin - side branches of medial cord, receiving fibers from C8, T1

course - passes between axillary artery and vein; then pierces pectoralis minor and enters deep surface of pectoralis major; although it is called medial for its origin from medial cord, it lies lateral to lateral pectoral nerve

structures innervated - pectoralis minor and sternocostal part of pectoralis major

origin - side branches of medial cord, receiving fibers from C8, T1

course - smallest nerve of plexus; runs along medial side of axillary and brachial veins; communicates with intercostobrachial nerve

structures innervated - skin of medial side of arm, as far distal as medial epicondyle of humerus and olecranon of ulna

origin - side branches of medial cord, receiving fibers from C8, T1

course - initially runs with ulnar nerve (easily confused) but pierces deep fascia with basilic vein and enters subcutaneous tissue, dividing into anterior and posterior branches

structures innervated - skin of medial side of forearm, as far distal as wrist

origin - terminal branch of posterior cord, receiving fibers from C5 (primarily) and C6

course - exits axillary fossa posteriorly, passing through quadrangular space with posterior circumflex humeral artery; gives rise to superior lateral brachial cutaneous nerve, then winds around surgical neck of humerus deep to deltoid

structures innervated - glenohumeral (shoulder) joint; teres minor and deltoid muscles; skin of superolateral arm (over inferior part of deltoid)

origin - larger terminal branch of posterior cord (largest branch of plexus),receiving fibers from C5 - T1

course - exits axillary fossa posterior to axillary artery; passes posterior to humerus in radial groove with deep artery of arm, between lateral and medial heads of triceps; perforates lateral intermuscular septum; enters cubital fossa, dividing into superficial (cutaneous) and deep (motor) radial nerves

structures innervated - all muscles of posterior compartments of arm and forearm; skin of posterior and inferolateral arm, posterior forearm,and dorsum of hand lateral to axial line of digit 4

origin - posterior aspect of anterior rami of C5 and C6 (primarily), C7

course - passes through cervicoaxillary canal, descending posterior to C8 and T1 roots of plexus (anterior rami); runs inferiorly on superficial surface of serratus anterior

structures innervated - serratus anterior

origin - side branch of posterior cord, receiving fibers from C5

course - passes posteriorly, entering subscapularis directly

structures innervated - superior portion of subscapularis

origin - side branch of posterior cord, receiving fibers from C6

course - passes inferolaterally, deep to subscapular artery and vein

structures innervated - inferior portion of subscapularis and teres major

origin - side branch of posterior cord, receiving fibers from C6, C7 (primarily), C8

course - arises between upper and lower subscapular nerves and runs inferolaterally along posterior axillary wall to apical part of latissimus dorsi

structures innervated - latissimus dorsi

origin - only branch off first part of axillary artery

course - runs anteromedially along superior border of pectoralis minor; then passes between it and pectoralis major to thoracic wall; helps supply 1st and 2nd intercostal spaces and superior part of serratus anterior

origin - first branch off second part of the axillary artery

course - curls around superomedial border of pectoralis mino; pierces costocoracoid membrane (clavipectoral fascia); divides into four branches: pectoral, deltoid, acromial, and clavicular

origin - second branch off the second part of the axillary artery

course - descends along axillary border of pectoralis minor; follows it onto thoracic wall, supplying lateral aspect of breast

origin - third part (as largest branch of any part) of axillary artery

course - descends from level of inferior border of subscapularis along lateral border of scapula, dividing within 2-3 cm into terminal branches, the circumflex scapular and thoracodorsal arteries

origin - third part (sometimes via a common trunk) of axillary artery

course - encircle surgical neck of humerus, anastomosing with each other laterally; larger posterior branch traverses quadrangular space

Superior thoracic artery

thoracoacromial artery

lateral thoracic artery

circumflex humeral (anterior and posterior) arteries

subscapular artery

Musculocutaneous nerve

lateral pectoral nerve

lateral root of the median nerve

medial pectoral nerve

medial cutaneous nerve of the arm

medial cutaneous nerve of the forearm

medial root of median nerve

ulnar nerve

upper subscapular nerve

thoracodorsal nerve (middle subscapular nerve)

lower subscapular nerve

radial nerve

axillary nerve