CHAP, v.] THE CAT'S MUSCLES. 145 



MUSCLES OF THE LIMBS. 

 THE rORE-LIMT5. 



§ 9. Scrratns magnm. — This is a large sheet of muscle which 

 arises by ten digitations (the anterior four being wider than the 

 others) from the sternal aspect of the first ten ribs. It is inserted 

 into the vertebral margin of the scapula. The scaleni muscles dip 

 in between the second and third, and between the fourth and fifth 

 digitations of this muscle. 



The Icvaiot' aiigidi scapnke is a second sheet of muscle similar to 

 the preceding, and so closely connected with it that they can only 

 be separated artificially. It is inserted into the scapula with the 

 serratus magnus. It arises from the transverse processes of the last 

 five cervical vertebra?. The combined insertion of this and the 

 serratus extends along the whole vertebral margin of the scapula 

 posteriorly from a point just in front of the insertion of the rhom- 

 boideus capitis. 



The combined action of these two muscles is to suspend the body 

 as in a hammock from the summits of the two fore-limbs. It aids 

 also in any pushing action of the fore-limbs, and therefore in 

 springing. 



The cJcido-mastoid has been already described.* 

 The r/ioniboidens major is a sheet of muscle which takes origin 

 (beneath the trapezius) from the neural spines of the six hinder 

 cervical and the four or five most anterior dorsal vertebrae. It is 

 inserted into the vertebral margin of the scapula; its insertion 

 extending forwards about half an inch in front of the vertebral end 

 of the spine of the scapula. 



The rliomhoideus capitis is a long, narrow muscle which arises 

 from the lambdoidal ridge, and is inserted into the vertebral margin 

 of the scapula, just in front of the insertion of the rhomboideus 

 major, dipping in between the insertion of the last-named and that 

 of the serratus magnus. 



Pectoralis. — This is a very large muscle which consists of five 

 portions, all going from the sternum and sternal ends of the costal 

 cartilages to the upper arm. No part goes to the coracoid. 



(1.) The most superficial part (Fig. 79, 7;"^) is a long, rather narrow, 

 band of parallel fibres which arises from beneath the manu- 

 brium and attachment of the first two costal cartilages. It is 

 inserted partly into the fascia of the flexor surface of the fore- 

 arm, but partly joins the cephalo-humeral and is inserted 

 with it. 

 (2.) The second and largest part (j)^) arises from the manu- 

 brium and sternum as far back as the fourth costal cartilage. 

 It also arises from fascia just in front of the manubrium. It 

 is inserted into the outer side of the deltoid ridge of the 



* See ante, p. 134. 



