34 LABORATORY DIRECTIONS 



Adductor, a muscle which tends to draw a part toward the 

 median line. 



Abductor, a muscle which tends to draw a part away from the 

 median line. 



Rotator, a muscle which rotates a limb, or part of it, on its 

 long axis. 



There are about five hundred voluntary muscles in the cat. 

 While the descriptions given here are limited to the hind leg, 

 dissect as many of the other muscles as you wish. The muscles 

 are described in the order in which they are most conveniently 

 dissected. Careful comparison of the muscles with the descrip- 

 tions will usually enable you to make certain that you have the 

 right muscle. In case of doubt refer to Reighard and Jennings, 

 ''Anatomy of the Cat.'' Always have a skeleton before you. 

 First find the origin and insertion of the muscle on the skeleton, 

 and then find it on the specimen. Observe the direction in 

 which the muscle fibers run; they are not always parallel to the 

 long axis of the muscle. Trace each muscle to its origin and 

 insertion, but do not remove a muscle at its origin or its insertion 

 unless specifically told to do so. However, a muscle may be cut 

 through the middle to expose underlying muscles. Try not to 

 cut the larger blood vessels; a few will be mentioned as the dis- 

 section proceeds. 



Demonstrate dissections to the instructor, and be prepared 

 at any time to point out any muscle and give its origin, insertion, 

 and action. A clean-cut dissection will have the fat and con- 

 nective tissue removed so that the muscles stand out clearly. 



Superficial Muscles of the Thigh 



Remove the fat and superficial fascia from one thigh and 

 shank. If the cat is a male, be careful not to injure the spermatic 

 cord which emerges from the body cavity and extends to the 

 testis. Place the cat ventral side up. 



I. Sartorius. — There are only two superficial muscles on 

 the median side of the thigh; both are broad and fiat. The 

 sartorius covers the cephalic half of the median surface of the 

 thigh; the gracilis, to be studied next, covers the caudal half. 

 Distally these two muscles nearly meet; proximally they diverge 

 leaving between them a shallow depression known as Scarpa's 



