MUSCLES OF THE BODY. 147 



Insertion (Fig. 81, <■/) into the humerus along a line which 

 forms the ventral border of the bicipital groove at the proximal 

 end of the bone, passes thence onto the pectoral ridge and 

 continues in the direction of the pectoral ridge nearly as far as 

 the middle of the length of the humerus. The cranial and 

 caudal fibres are inserted by means of a thin tendon ; the 

 middle fibres directly. The cranial border of the tendon of 

 insertion is continued as a thin tendon to the coracoid process ; 

 it is closely united with the insertion of the supraspinatus. 



Relations. — By its outer surface with the pectoralis major 

 (Fig. 65, /) over its cranial half; with the cutaneus maximus, 

 latissimus dorsi (Fig. 65, q), and integument over its caudal 

 half. By its inner surface with the xiphihumeralis (Fig. 65, /), 

 rectus abdominis (Fig. 73, k), and a mass of fat in the axilla. 

 The tendon of the xiphihumeralis is also connected with its 

 inner surface near its insertion. Its cranial border is free. Its 

 caudal border is in relation at its medial end with the xiphi- 

 humeralis, at its lateral end with the tendon of the latissimus 

 dorsi (Fig. 65, q). 



Action. — Draws the arm toward the middle line. 



M. xiphihumeralis (Fig. 65, q'). — A long, thin, narrow 

 muscle which may be considered as part of the pectoralis 

 minor. 



Origin a median raphe along the xiphoid process or at an 

 angle to the median line on the rectus abdominis muscle. It 

 passes craniad, becoming gradually smaller, and about two 

 centimeters from its insertion ends in a thin tendon. 



Insertion. — It ends in a flat tendon which in passing is con- 

 nected by a strong fascia with the tendon of the latissimus 

 (Fig. 65, ^). It passes along the inner surface of the pectoralis 

 minor {o) to be inserted with its cranial fibres near the ventral 

 border of the bicipital groove. 



Relations. — Outer surface with the cutaneus maximus at 

 its medial end, with the pectoralis minor {ci) at its distal end. 

 Inner surface with the external oblique (Fig. 6^, f), the rectus 

 abdominis (Fig. 73, k), and a mass of fat in the axilla. Borders 

 free. Some of the fibres of the cutaneus maximus are attached 

 to its outer surface. 



