M. ENTOPECTOBALIS. 243 



DV. CEPHALICA. 



§ 658. Synonymy.— '•Sternotrochiterien," S.D., A, II, 337; pectoralis, part 3 (in 

 part), Miv., B, 147. 



Figures.— Ectal aspect (73, left side); humeral end, reflected (73); insertion area (68, 

 69, 70). 



General Description.— A thick band, much widened at the 

 sternum ; from all the mesosternehrce, excepting the first and sixth 

 — ov fifth and sixth — and from the intervening and terminal nodes, 

 to the head of the humerus. 



Exposure. — Both borders have been exposed, the cephalic by 

 the reflection of the ectopectoralis, the caudal by the reflection of 

 the caudal division of the entopectoralis . 



Dissection. — The humeral end must be reflected with great care, 

 and the preliminary examination should be made with the tracer 

 rather than with the scalpel. Particular pains should be taken to 

 avoid cutting or breaking a slender tendon which sometimes extends 

 from the cephalic border, close to the humerus, to the coracoid 

 process of the scapula (Fig. 73, Tn. x.). 



The ectal fibers of the muscle cease at the supraspinatus, and 

 seem to be inserted upon it, but the coracoid margin of the latter 

 muscle may be dissected up for 1-5 mm. ; there will be exposed 

 a tendinous continuation of the entopectoralis, which, as to its 

 cephalic half, cannot be separated farther from the tendon of the 

 swpraspinatus without cutting the tendinous fibers. 



§ 659. Insertion. — At the border of the overlapping supraspi- 

 natus the fleshy part of the present muscle is replaced by a tendon 

 which is attached to the caudal aspect of the trochiter, and along its 

 ventral border ; this attachment is in line with the insertion of the 

 caudal division, and terminates 1-2 mm. from its proximal end. 

 The caudal half or third of this tendon is thin ; the rest is thick and 

 fused with the ental surface of the tendon of the supraspinatus so 

 that the respective areas of attachment can be ascertained only 

 approximately. The latter muscle, however, is on the ectal side, 

 and occupies the crest and ceplialic aspect of the trochiter. 



In addition to the tendon of direct insertion, a slender band 

 sometimes extends from the cephalic border, just at the junction of 

 the muscle and the tendon, and is attached to the border of the 

 coracoid process between its tip and the prominent coracoid lip of 

 the glenoid fossa. This tendon probably represents the coracoid 



