152 THE ARTISTIC ANATOMY OF ANIMALS 



and backwards, covering the scapulo-humeral angle — that is, 

 the region known as the point of the shoulder or arm — and 

 is inserted into the anterior border of the humerus, the 

 border which, limiting anteriorly the musculo-spiral groove, 

 forms a continuation of the deltoid impression. On account 

 of the regions with which it is related, Bourgelat named this 

 muscle the muscle common to the head, neck, and arm. 



It is at the level of the scapulo-humeral angle that the 

 vestiges of the clavicle are found. 



This bone is represented in some animals — the pig, ox, 

 and horse — by a single tendinous intersection, more or less 

 apparent, which extends transversely from the scapula to 

 the anterior extremity of the sternum. In the dog and the 

 cat, we find, besides, on the deep surface of the muscle and 

 at the level of this tendinous intersection, the rudiment of 

 the clavicle of which we made mention in the section on 

 Osteology (see p. 25). 



It is beneath the intersection, the existence of which we 

 have just pointed out, that is found that portion of the 

 mastoido-humeral muscle which corresponds to the clavicular 

 fasciculi of the deltoid ; that portion which is situated above 

 the intersection corresponds to the clavicular fibres of the 

 sterno-cleido-mastoid and of the trapezius. 



The mastoido-humeral presents certain varieties in dif- 

 ferent animals. 



In the dog and the cat, this muscle, which is blended above 

 with the sterno-mastoid (see p. 153), to be inserted with it 

 into the mastoid process and the mastoid crest, covers the 

 neck for a considerable extent from the superior curved line 

 of the occipital bone to which it is attached, to the trapezius 

 with which it unites posteriorly, but from which it separates 

 below. Between these two extreme points of its superior 

 portion it is attached to the cervical ligament. 



In the pig and in ruminants, in which the trapezius 

 approaches more closely to the head, the mastoido-humeral 

 occupies, in consequence, a less extent of the cervical region. 



In the horse, the mastoido-humeral neither covers the 

 neck nor joins the trapezius ; indeed, we have already 

 shown that it is separated by a considerable distance from 



