346 UR. C. K. SONNTAa ON TllK ANATOMY, 



tiutei'ior thoracic uoi'vc iiiui the tlioviicico-acromial vessels, but it 

 is not pierced by the cephalic vein which runs through it in Man 

 and many other nianmials. Tiie fibres run transversely below 

 the costo-coracoid ligament. 



The deltoid, covered by dense fascia, is coarsely fa,sciculate. It 

 arises from the front of the outer half of the clavicle and the outer 

 border of the acronuon process. A second part has an extensive 

 aponeurotic and fa.scia] origin from the whole length of the lower 

 border of tlie spine of the scapula, and from the fascia over the 

 entire infra-spinatus. At the inferior angle of the scapula, 

 the fascial origin blends with serratus niagnus, the rhomboids, 

 teres major, and latissimus dorsi. It conceals a bursa, which in- 

 tervenes between the acromion and upper end of the humerus, 

 but does not communicate with the shoulder joint. One large 

 and several small branches of the circumtlex nerve, a.nd 

 branches of the circurailex arteries are seen entei'ing its deep 

 aspect. Huniphry found it a.dherent to the brachialis anticus 

 (26), but Macalister (33) denied that it adheres to the triceps 

 and brachialis anticus. Wilder (53) points out that the attach- 

 ment to the fascia, over the infra-spinatus and the axillary border 

 of the scapula enables the animal to swing the ixinn far back. 

 The muscle libres all converge to be inserted into the usual 

 deltoid a.rea. on the shaft of the humerus. The insertion is 

 embraced by the brachialis anticus. 



Scapular Mitsdes ■ — All observers are agreed that the infra- 

 spinatus greatly exceeds the supra -spinatus in size, and both arise 

 from the whole of the scapular foss;e to wliich they iW'P attached. 

 They are inserted as in Man into impressions on the great 

 tuberosity. Corresponding vessels and nerves pass into them as 

 in Man. The infra-spinous fossa is deep, being enclosed between 

 the prominent spine a.nd a. thickening of the axillary border of 

 the scapula. The teres minor arises from the lower border of the 

 lip of the glenoid cavity and lateral half of the axillary border of 

 the scapuhi. It is inserted into tiie lowest part of the great 

 tuberosity of the humerus and the upper half inch of the shaft 

 of the bone. Chanipnevs (11) gives its origin as the mid third 

 of the axillary border and the adjacent part of the infra-spinous 

 fossa, and Hepburn (34) records its origin from the upper two- 

 thirds of the axillary border. The teres major arises from the 

 medial half of the axillary border of the scapula, and is inserted 

 into the inner lip of the bicipital groove. It is strongly fused 

 with the latissimus dorsi. The subscapidaris arises from the 

 whole of the subscapular fossa, and tendinous bands run through 

 between the bundles of fibres to the bone. It has no origin from 

 fascia over it. The muscular mass converges, and is inserted by 

 three tendons into the lesser tuberosity and the shaft of the 

 humerus over a quarter of an inch below it. Some of the deep 

 fibres are directly inserted into the capsule of the shoulder joint. 

 The coraco-hrachiaUs is fleshy throughout. It arises along 

 with the short head of the biceps from the tip of the coracoid 



