./AM/. FOREARM, HAND. POSTERIOR I'.IKT. 



i 'tit this muscle at its insertion, turn it back (Fig. -54), and find the 

 Is ami nerves the suprasotpular that supply this region. 

 The suprascapular artery and nerve will come into view as you turn aside 

 the. supraspinatus muscle. (Figs. 249-254.) The nerve you will trace through 

 the suprascapular foramen under the transverse ligament. (Fig. 252.) The artery 

 cross,--, the transverse ligament. (Fig. 252.) Each structure divides into supra- 

 spinous anil infraspinous brandies. Trace these vessels and nerves out to their 

 respective localities of distribution. (Fig. 254.) 



The anastomosis between the suprascapular artery and the dorsal branch of 



the subscapular takes place in the infraspinous fossa, on the bone. Find this. 



249.) Anastomosis about the shoulder includes the following arteries, 



which you may now demonstrate. (Fig. 254): Circumflex, subscapular, dorsalis 



Transverse ligament 



Conoid ligament 



Acromio-clavicular 



ligament 



Tendon of infra- 

 apiuatus and terea 

 minor 



Inferior transverse 

 or spino-Rlenoid 

 ligament 

 Capsule of shoulder 



FIG. 252. POSTERIOR VIEW OF TDK SHOULDER-JOINT, SHOWING ALSO THE ACROMIO- 

 ei.AvicuLAR JOINT AND THE PROPER LIGAMENTS OF THE SCAPI-I.A. 



scapula.', suprascapular, posterior scapular artery, a continuation of the trans- 

 versalis colli, a branch of the thyroid axis of the subclavian. 



The triceps muscle (Fig. 253) has three heads. The longer scapular 

 head you will now very carefully trace to the axillary border of the scapula, 

 immediately below the glenoid fossa. As you have already observed, this head 



sts in forming boundaries for the quadrangular space and also for the two 

 triangular spaces. The whole posterior surface of the humerus is occupied by 

 the inner and outer heads of the triceps muscle, and the musculo-spiral groove. 



Dlsstction. Locate the musculo-spiral nerve and the superior profunda 

 artery in the second triangle. (Fig. 249.) Now the nerve will pass between the 

 bone and muscle. Cut the muscle in a line corresponding to the course of the 

 nerve, until you come to a point two inches above the outer condyle. The mus- 

 cular mass attached to the posterior surface of the humerus above the groove, in 



