MUSCLES OF THE BODY. 145 
able number of not always clearly separated bundles in the cat. 
We shall distinguish by name four such bundles; these might 
be, and frequently are, further subdivided. 
M. pectoantibrachialis (Fig. 65, #).—This is a small flat 
bundle about one or two centimeters wide, forming the most 
superficial portion of the pectoralis group. 
Origin on the lateral surface of the manubrium. The 
muscle passes laterad onto the arm and is zuserted by a flat 
tendon into the superficial fascia of the dorsal border of the 
forearm, near the eblow-joint. The tendon is continuous 
craniad with the border of the clavobrachial (£), so that a bundle 
of fibres may pass from this muscle to be inserted with the 
clavobrachial, or a bundle from the clavobrachial to be inserted 
with this. The tendon is continuous caudad with that of the 
epitrochlearis (7). The fascia of insertion may be traced to an 
attachment into the dorsal border of the ulna. This muscle 
usually receives near its insertion a slip, sometimes called its 
caudal division, from the deep layer of the pectoralis major. 
Relations.—Outer surface with the integument. Inner sur- 
face with both divisions of the pectoralis major (7) on its medial 
two-thirds, and with the biceps (¢) and bicipital arch (¢’) in its 
lateral one-third. The cranial border is closely applied to that 
of the clavobrachial (£), except at the two ends. 
Action.—Draws the arm mediad. 
M. pectoralis major, or ectopectoralis (Fig. 65, /, /').— 
In this it is usually possible to distinguish a superficial and a 
deep layer. 
The superficial (/’) layer is a flat band of fibres one or two 
centimeters wide. 
Origin from a raphe in the midventral line, along the 
cranial half of the manubrium and for five to ten millimeters 
craniad of it. 
Insertion (Fig. 81, f).—The pectoral ridge of the middle 
third of the shaft of the humerus, slightly dorsad of the line of 
insertion of the deep portion. 
Relations. — Outer surface with the clavobrachial (Fig. 
65, #) and integument, the medial end caudally with the 
pectoantibrachialis (m), and the distal end with the brachialis 
