242 ANATOMICAL TECHNOLOGY. 



sometimes one or both of the divisions show signs of subdivision. 

 In the specimen figured (Fig. 72), the cephalic division presents two 

 well-marked subdivisions. 



Near the humerus the interval between the two divisions is 

 usually wide, but toward the sternum the cephalic border of the 

 caudal overlaps the caudal border of the cephalic division, and 

 sometimes their separation cannot be effected without cutting fibers. 

 At the sternum, however, the overlapping sometimes hardly exists. 



The caudal border has been exposed during the dissection of the 

 latissimus and dermo-Tiumeralis, whose humeral ends are connected 

 with this muscle at the bicipital arch (Fig. 73) ; but the sternal half 

 of this border is closely united with the cephalic border of the 

 xiphi-Tiumeralis, which it overlies in its humeral half. The xiphi- 

 Tiumeralis may be recognized by its loose and wide origin at the 

 epigastrium. Carefully disengage the two muscles at their crossing, 

 then transect the caudal division of the entopectoralis. 



657. Origin. By fleshy or short tendinous fibers from the 

 border of the last 2 or 3 mesosternebrse, and sometimes from the 

 cephalic part of the xiphisternum, and from the intervening nodes. 



Insertion. Variable and complex, and not easily described, 

 excepting in connection with the other elements of the bicipital arch. 

 At about 3 cm. from its attachments to the ventral border of the 

 humerus the caudal border is connected with the latissimus. and its 

 ental aspect, along an oblique line passing proximo-cephalad, is 

 sometimes united with the thin tendon of the xiphi-Jiumeralis. For 

 the sake of distinctness, this union may be severed close to the 

 ental surface, some fasciae passing from the caudal border of the 

 tendon to the surface of the M. biceps may be removed, and the 

 extent of the true insertion may be seen more distinctly. 



Like that of the caudal division of the ental layer of the ecto- 

 pectoralis, the insertion is partly muscular and partly tendinous. 

 The line of attachment is about 3 cm. long, and extends from the 

 base of the trochiter along the ventral border of the humerus to a 

 point .near the junction of the second and middle fifths of the length 

 of the whole bone, and opposite the junction of the muscular and 

 tendinous parts of the insertion of the caudal division of the ental 

 lamina of the ectopectoralis. The proximal third or two fifths of the 

 insertion is fleshy, the rest is a thin tendon about 1 cm. long. 



