THE RABBIT 315 



On the lateral surface of the thigh a thick membrane will be 

 seen, which covers the anterior half of it ; this is the fascia lata. 

 A very long, slender muscle, the sartorius, is present along its 

 anterior border and forms the anterior margin of the thigh, extend- 

 ing from the ilium to the upper end of the tibia. Just posterior 

 to the fascia lata is a large muscle, the biceps femoris, which oc- 

 cupies half the lateral surface of the thigh and consists of two 

 portions, one of which extends from its origin in the spinous proc- 

 esses of the sacral and caudal vertebrae to the patella, and the 

 other from its origin in the tuberosity of the ischium to the fascia 

 lata; their action is to draw the thigh inward and the shank 

 upward. 



Exercise 37. Draw the lateral aspect of the animal and place in it 

 the outlines of these muscles, showing the directions of their fibers. 

 Carefully label all. 



Study the muscles of the ventral surface of the trunk and the 

 legs. Covering the abdomen are the external oblique muscles, 

 their aponeuroses extending to the linea alba in the midventral 

 line. Through the semitransparent aponeuroses will be seen the 

 two rectus abdominis muscles, one on each side of the linea alba, 

 —long, narrow muscles which extend in the midventral area from 

 the pubis to the ribs. Covering the breast are the pectoral mus- 

 cles. These constitute a group of five large muscles, more or less 

 connected with one another, which extend from the sternum to 

 the humerus, with some fibers passing to the clavicle and the 

 spine of the scapula; their action is to draw the arm down and 

 back. Posterior to the distal portion of the pectorals, and between 

 them and the latissimus dorsi, portions of three muscles come into 

 view. They are the serratus magnus, which arises from the third 

 to the ninth ribs by several slips which appear just below the 

 latissimus dorsi, and has its insertion in the upper border of the 

 scapula ; and the subscapularis and teres major, two muscles which 

 lie side by side in the axillary region, and arise from the medial 

 and axillary borders of the scapula and are inserted in the 

 humerus. Their action is to draw the arm inward and downward. 



On the inner surface of the upper arm three muscles appear. 



