THE ANATO:vrY OF THE ELK. 



379 



posterior costa of tbe scapula, and also from its posterior angle. It passes 

 downwards and forwards, and is inserted by a ribbon-like tendon into the 

 inner surface of the shaft of the humerus, about 2 inches below the head. 

 Po steriorly this muscle receives the anterior fibres of the great dorsal 

 muscle. 



Teres minor (Short Abductor of the Arm) arises from the middle half of 

 the posterior border of the scapula. The fibres run downwards and for- 

 wards, parallel to the subspinatus, and terminate by being inserted into 

 the fascial origin of the external head of the triceps. 



Superspinatus {Antea spinatus) arises from the supra-spinous fossa of 

 the scapula and from the fascia covering it, and is inserted into the upper 

 border of the great tuberosity of the humerus, as well as into its lesser tu- 

 berosity. Between these bony attachments the fibres are inserted in a 

 similar manner to those of the deep pectoral muscle, by means of a strong 

 fibrous band which arches over the long head of the biceps. 



Subspinatus arises from the surface of the subspinous fossa and from 

 the fascia which covers the muscle. The fibres end in a stout tendon which 

 is attached to the outer surface of the great tuberosity of the humerus. 



Subscapularis arises from the ventral surface of the scapula, with the ex- 

 ception of that portion which receives the insertion of the great serratus ; 

 its fibres pass downwards to be inserted by means of a strong tendon into 

 the inner surface of the lesser tuberosity of the humerus. At its origin 

 this muscle is partially divided into three portions, the central one being 

 bridged over by the tendinous arch of the great serratus. 



Anterior Humeral Begion. 



Coraco-humeralis arises along with the biceps from the coracoid process 

 of the scapula, and is attached by means of a linear insertion into the 

 whole length of the inner surface of the shaft of the humerus. 



Long Flexor of Forearm (Biceps) is a single-headed muscle which arises 

 by means of a thick flattened tendon from the coracoid process of the sca- 

 pula. This tendon, passing over a trochlear surface on the superior ex- 

 tremity of the humerus, gives place to a fleshy belly which terminates 

 in a strong flattened tendon. This tendon divides into two parts, of which 

 the outer is inserted into the inner border of the radius close to its head, 

 whilst the inner, passing off at right angles, is inserted into the inner border 

 of the olecranon process of the ulna. 



Short Flexor of Forearm arises from the posterior surface of the shaft of 

 the humerus immediately below the head, as well as from the outer sur- 

 face of the root of the great tuberosity. The muscle winds spirally round 

 the external surface of the humerus, and is inserted by a flattened tendon 

 into the inner border of the shaft of the ulna just below the olecranon 

 process. 



