122 THE MUSCLES. 
Relations.—Its outer surface is covered caudad by the 
cutaneus maximus, and craniad by the spinotrapezius (Fig. 
68, 7) and the long head of the triceps (Fig. 68, £). The 
cranial border comes into relation with the spinotrapezius (/) 
and teres major (Fig. 77, ¢). The caudal border is in contact 
at the ventral end with the xiphihumeralis (Fig. 65, f) and 
pectoralis minor (Fig. 65, 0). The inner surface of the latissi- 
mus covers near its cranioventral end parts of the xiphihumer- 
alis (Fig. 68, 7), pectoralis minor (Fig. 68, 0), teres major 
(Fig. 77, ¢), and serratus anterior (Fig. 73, 7). The caudal 
border covers a portion of the obliquus externus .abdominis 
(Fig. 68, #); the dorsal and middle portions cover parts of the 
longissimus dorsi (Fig. 69, 7”), the spinalis dorsi (Fig. 69, 2), 
the serratus posterior superior (Fig. 73, 2), and serratus pos- 
terior inferior (Fig. 73, 7). 
Action.—Pulls the arm caudodorsad. 
M. serratus anterior and levator scapule (Fig. 73, Zand /) 
in the cat are continuous at both origin and insertion, and it is 
barely possible to separate their contiguous borders without 
cutting the fibres. The muscle extends from the transverse 
processes of the last five cervical vertebra and from the first 
nine or ten ribs to the medial surface of the scapula near its 
vertebral margin (Fig. 78, c and @). 
M. serratus anterior (or serratus magnus) (Fig. 73, 2). 
Origin.—From the first nine or ten ribs in as many sub- 
divisions. The first subdivision arises from the whole or nearly 
the whole of the caudal border of the first rib. The next four 
or five arise either from the ribs or from the costal cartilages 
near or at their junction with the ribs. The last four subdivi- 
sions arise from the ribs at increasing distances from the carti- 
lages. The fibres converge and the subdivisions join one 
another. 
Insertion (Fig. 78, c) into a narrow area on the medial sur- 
face of the scapula near the vertebral border. The glenoid 
half of the insertion is by a short tendon, the remainder by 
muscle-fibres. 
Relations. —Outer (lateral) surface with the latissimus dorsi 
(Fig. 68, m), teres major (Fig. 77, ¢). subscapularis (Fig. 
