i6o THE ARTISTIC ANATOMY OF ANIMALS 



is also a thyro-hyoid, but because of its deep situation and 

 its slight importance it offers no interest from our point of 



view. 



Sterno-thyroid and the Sterno-hyoid Muscles. — These 

 two muscles, long, narrow, and flat, arise from the anterior 

 extremity of the sternum ; then, covering the anterior 

 surface of the trachea, they proceed to terminate, the one 

 on the thyroid cartilage, and the other on the hyoid bone. 

 The sterno-hyoid is superficial ; it covers the sterno-thyroid, 

 which, however, projects a little on its outer side. 



Omo-hyoid. — This muscle does not exist in the dog or 

 cat. It arises, in the horse, from the cervical border of the 

 scapula, where it blends with the aponeurosis that envelops 

 the subscapularis muscle, but in the pig and the ox it arises 

 from the deep surface of the mastoido-humeral muscle. It 

 is directed obliquely upwards and inwards, becoming super- 

 ficial at the internal border of the sterno-mastoid, and 

 is inserted into the hyoid bone. 



The region in which are united the portion of the neck 

 which we have just studied and the neighbouring part 

 of the thorax — that is, the breast — has certainly, in our 

 opinion, a form less expressive than the corresponding 

 region in man. 



In the latter, indeed, the fourchette of the sternum, with 

 the hollow which it determines, the heads of the clavicles, 

 and the sterno-cleido-mastoid muscles, by the elevations 

 which they produce, and the trachea, by the situation which 

 it occupies in the inferior part, constitute a whole in which 

 are admirably indicated, not only the forms of the organs 

 which constitute this region, but also the relations which 

 these organs have one with another; and, to a certain extent, 

 their respective functions. 



In making an exception in the case of the ox, in which a 

 fold of skin, the deidap, which passes from the neck to the 

 breast, constitutes an element of form which possesses 

 some expressive value ; in the horse and in the dog, which 

 possess no sternal fourchette and no heads of clavicles, the 

 bones and the muscles are found nearly on the same plane. 

 This produces a uniformity which is evidently inferior, from 



