MUSCLES OF THE THORACIC LIMBS. 159 



clavotrapezius (Fig. 68, d}\ other fibres have origin from the 

 clavicle and from a raphe laterad of the clavicle which is com- 

 mon to this muscle and the clavotrapezius. It passes distad 

 along the cranial surface of the arm, growing narrower as 

 it approaches the convexity of the elbow. 



Insertion. Eight to ten millimeters from the ulna it joins 

 the brachialis muscle (Fig. 79, z) to be inserted with it by a 

 flat tendon (Fig. 79, i ; Fig. 87, <:) upon a rough area on the 

 medial surface of the ulna just distad of the semilunar notch, 

 and about midway between the dorsal and ventral borders. 



Relations. Outer surface with the integument. Inner 

 surface with the pectoralis major (Fig. 65, /), biceps (Fig. 

 77, -), lateral head of the triceps (Fig. 75, //), acromiodeltoid 

 (Fig. 75, /"), and brachialis (Fig. 80, /i). Medial border with 

 the pectoantibrachialis (Fig. 65, m}. Lateral border free 

 except near the insertion, where it is in relation with the 

 brachialis. 



Action. Flexor of the antibrachium. 



M. supraspinatus (Fig. 75, a] occupies the whole of the 

 supraspinatus fossa of the scapula. It is covered by strong 

 fascia which stretches from the free edge of the spine to the 

 coracoid border of the scapula and to the coracoid half of its 

 vertebral border. 



Origin (Fig. 76, b} by fleshy fibres from the whole surface 

 of the supraspinatus fossa, from the above-mentioned fascia, 

 and from the subscapularis (Fig. 77, a) craniad of the coracoid 

 border of the scapula. 



Insertion (Fig. 83, a}. It passes over the capsule of the 

 shoulder-joint, to which it is closely attached, and is inserted 

 into the free border of the great tuberosity ventrad (or proxi- 

 mad) of the fossa for the infraspinatus (Fig. 83, c]. 



Relations. Outer surface with the spinotrapezius (Fig. 

 68, /), acromiotrapezius (Fig. 68, //), levator scapulae ventralis 

 (Fig. 68, /), clavotrapezius (Fig. 68, d\ and cleidomastoid 

 (Fig. 65, Ji}. Inner surface with the scapula. The distal end 

 of the coracoid border is closely related to the pectoralis minor 

 (Fig. 79, /). The glenoid border is related to the origin of 

 the deltoidei. 



