84 LABORATORY MANUAL OF HUMAN ANATOMY 



tions of the nerve closely in the different parts of the upper 

 arm. Branches in upper arm : 



(ba) Posterior cutaneous nerve of upper arm (N. cutaneus brachii 



posterior) (0. T. upper external cutaneous branch of mus- 

 culospiral). (Already studied; vide supra.) 



(bb) Muscular rami (rami musculares). 



(bba) To three heads of M. triceps brachii. 



(bbb) To M. anconaeus. 



(bbc) To M. brachioradialis (already studied). 



(bbd) To M. extensor carpi radialis longus (already 



studied). 



(bbe) To M. brachialis. 



(be) Posterior cutaneous nerve of forearm (N. cutaneus anti- 

 brachii dorsalis) (0. T. lower external cutaneous branch 

 of musculospiral. (See Fig 1 . 28.) 



(c) Deep artery of upper arm (A. prof undo, brachii) (0. T. superior 



profunda artery). 



Study its relations in all parts of its course. 

 Branches : 



(ca) Deltoid ramus (ramus deltoideus). 



(cb) Middle collateral artery (A. collateralis media). Note its 



contribution to the rete articulare cubiti. 



(cc) Radial collateral artery (A. collateralis radialis) (0. T. artic- 



ular branch of superior profunda). 



(cd) Nutrient arteries of the humerus (Aa. nutriciae humeri). 



These sometimes come from the brachial artery proper. 



(d) Other structures in back of arm. 



Dissect carefully above the back of the elbow 



(da) Ulnar nerve (N. ulnaris), through the sulcus N. ulnaris. 



(db) Superior ulnar collateral artery (A. ulnaris collateralis supe- 



rior) (0. T. inferior profunda). Note relation to rete 

 articulare cubiti. 



(dc) Ramus muscularis to medial head of M. triceps. This is 



sometimes called the " ulnar collateral nerve." 



(dd) Inferior ulnar collateral artery (A. collateralis ulnaris infe- 



rior) (0. T. anastomotica magna). Look for it beneath the 

 tendon of the M. triceps, a little above the olecranon. 



(de) Bursa subtendinea olecrani. 



Look for a bursa subcutanea olecrani also and a bursa 

 intratendinea olecrani. 



SHOULDER-JOINT (ARTICULATIO HUMERI, OR AR- 

 TICULATIO SCAPULOHUMERALIS). 



This joint is an enarthrosis. (What is meant by this state- 

 ment!) Review the muscles related to the joint and then remove 

 them as follows : 



Cut through the origins of the M. coracobrachialis and the 

 caput breve of the M. biceps brachii; divide the M. teres major 



