MYOLOGY 171 



pies the superior half, or third, of the internal surface of 

 the humerus, is visible only when the arm is abducted, 

 and then especially when it approaches the vertical posi- 

 tion ; indeed, it is only in this attitude that the region 

 which it occupies is accessible to view. 



But an analogous attitude not being possible in domestic 

 animals, in which the arm is fixed along the corresponding 

 parts of the trunk, the result is that the coraco-brachialis is 

 always covered, and that, consequently, it presents nothing 

 of interest from our point of view. We speak of it, then, 

 merely in order to complete the series of the muscles of the 

 anterior surface of the arm, among which we rank it, in spite 

 of the fact that in veterinary anatomy it is described as a 

 muscle of the shoulder. 



It arises above from the coracoid process, and thence 

 passes downwards towards the internal surface of the 

 humerus into which it is inserted, more or less high up, 

 according to the species. The coraco-brachialis is an 

 adductor of the arm. 



Posterior Region. 



Triceps Cubiti (Fig. 68, 23, 24 ; Fig. 69, 20, 21 ; 

 Fig. 70, 28, 29 ; Fig. 72, 13, 14, 15, 16).— This muscle, which 

 is voluminous in the quadrupeds with which we are here con- 

 cerned, fits more or less completely the angular space between 

 the scapula and the humerus. Its bulk forms a thick 

 prominence, which surmounts the elbow and the forearm. 

 . We should say, with regard to this mass, that if the deltoid 

 does not constitute in quadrupeds a prominence sufficient to 

 remind one of that which this muscle produces in man, 

 the triceps, in producing an analogous elevation, seems to 

 replace in the general form of the body the relief which the 

 deltoid is incapable of producing. 



The triceps is divided into three portions, which, as in 

 man, have the names middle, or long head ; external and 

 internal heads. But that which renders the nomenclature a 

 little complicated is that veterinary anatomists have given 

 other names to these three parts : that of great extensor of 

 the forearm (caput magnum) to the long head ; the short 



