56 ANAloMY IX A NUTSHELL. 



A.ction.- -Rotates head of humerus outward. 



Nerve Slpply. — Fifth and Sixth cervical through the suprascapular nerve. 



Blood Supply. Suprascapular artery. 



Subscapulars. Description. — The subscapular fascia is a thin mem- 

 brane attached to the entire circu inference of the subscapular fossa, and afford- 

 in-- attachment by its inner surface to some of the fibers of the Subscapularis 

 muscle. The Subscapularis is a large triangular muscle which fills up the sub- 

 scapular fossa. The muscle terminates in a tendon which is in close contact 

 with the anterior part of the capsular Ligament of the shoulder- joint and glides 

 over a large bursa, which separates it from the base of the coracoid process. 

 This bursa communicates with the cavity of the joint by an aperature in the 

 capsular ligament. It- anterior surface forms a considerable part of the pos- 

 terior wall of the axilla, and its lower border is contiguous with the Teres major 

 and Latissimus dorsi muscles. 



Origin. — (Plate XXI.) — From the inner two-thirds of the subscapular 

 fossa, with the exception of a narrow margin along the posterior border, and the 

 surface- at the superior and inferior angles; also from the lower two-thirds of 

 the groove on the axillary border of the bone. Some fibers arise from tendinous 

 lamina', which intersect the muscle, and are attached to ridges on the bone, 

 and others form an aponeurosis which separates the muscle from the Teres 

 major and the long head of the Triceps. 



Insertion. — Lesser tuberosity of the humerus. (Plate XXIII.) 



A.CTION. — Rotates head of humerus inward. 



Nerve Supply. — Upper and lower subscapular (first and third.) 



Blood Supply. Subscapular artery. 



Teres minor.— (Plates XXVIII-XVIII.) — Description. — This is a narrow, 

 elongated muscle lying between the Infraspinatus and Teres major, being sep- 

 arated from the latter anteriority by the long head of the Triceps. 



Origin.— Upper two-thirds of dorsal surface of axillary border of the 

 scapula and from the two aponeurotic laminae, one of which separates it from 

 the Infraspinatus, the other from the Teres major. (Plate XX.) 



Insertion.- bower facet on greater tuberosity of humerus and bone be- 

 low. (Plate XXII.) 



A.CTION. Rotates head of humerus outward. 



Xi:i;\i.Si pply.— Fifth cervical through the circumflex. 



Blood Supply. -Infrascapular from dorsalis scapulae, circumflex arteries. 



LESSON XII. 



Teres major. Description.— (Plates XXVIII-XVIII.)— This is a thick, 

 but somewhat flattened muscle, lying immediately below the Teres minor. Its 

 fibers are directed upward and outward and terminate in a tendon about two 

 inches in length. This tendon, at its insertion, lies behind that of the Latissi- 

 mus dorsi, from which it is separated by a synovial bursa, the two tendons, 

 however, being united along their borders for a short distance. The axillary 

 vessels and the brachial plexus of nerves lie upon its anterior surface. Its 



