SCAPULAR REGION. 



379 



The Infraspinatus is a thick triangular muscle, which occupies the chief part 

 of the infraspinous fossa, arising by flesy fibres, from its internal two-thirds; 

 and by tendinous fibres, from the ridges on its surface. It also arises from a 

 strong fascia which covers it externally, and separates it from the Teres Major 

 and Teres Minor. The fibres converge to a tendon, which glides over the con- 

 cave border of the spine of the scapula, and, passing across the capsular liga- 

 ment of the shoulder-joint, is inserted into the middle facet on the great tube- 

 rosity of the humerus. The tendon of this muscle is occasionally separated 

 from the spine of the scapula by a synovial bursa, which communicates with 

 the synovial membrane of the shoulder -joint. 



Fig. 238. Muscles on the Dorsum of the Scapula and the Triceps. 



Relations. By its posterior surface, with the Deltoid, the Trapezius, Latissimus 

 Dorsi, and the integument. By its anterior surface, with the scapula, from which 

 it is separated by the suprascapular and dorsalis scapula? vessels, and with the 

 capsular ligament of the shoulder-joint. Its lower border is in contact with the 

 Teres Minor, and occasionally united with it, and with the Teres Major. 



The Teres Minor is a narrow, elongated muscle, which lies along the inferior 

 border of the scapula. It arises from the dorsal surface of the axillary border 

 of the scapula for the upper two-thirds of its extent, and from two aponeurotic 

 larninaB, one of which separates this muscle from the Infraspinatus, the other 

 from the Teres Major; its fibres pass obliquely upwards and outwards, and ter- 

 minate in a tendon, which is inserted into the lowest of the three facets on the 

 great tuberosity of the humerus, and, by fleshy fibres, into the humerus imme- 

 diately below it. The tendon of this muscle passes across the capsular ligament 

 of the shoulder-joint. 



Relations. By its posterior surface, with the Deltoid, Latissimus Dorsi, and 

 integument. By its anterior surface, with the scapula, the dorsal branch of the 

 subscapular artery, the long head of the Triceps, and the shoulder-joint. By 



