6 THE SURGICAL ANATOMY OF THE HORSE 



which corresponds to the inferior border of the gland. The anterior 

 extremity of this border indicates the position where Stenson's Duct 

 leaves the gland. The seat of operation in Hyovertobrotomy is in the 

 area described. 



The next step in the examination is to carefully locate the position 

 of the temporo-maxillary joint. This may be done by following the 

 posterior border of the vertical ramus upwards until the prominence 

 formed by the external extremity of the condyle of the inferior maxilla 

 is felt. The joint becomes more noticeable if the fingers be inserted in 

 the interdental space, and the animal be thus caused to move the joint. 



Curving round the posterior border of the vertical ramus, just below 

 the condyle, is the transverse facial artery, one of the terminal branches 

 of the superficial temporal division of the external carotid. The artery 

 runs forwards, and the pulsation of the vessel may be easily telt. 

 Accompanying this artery we have the seventh cranial nerve, otherwise 

 the facial, together with the sub-zygomatic branch of the inferior 

 maxillary division of the fifth cranial nerve. 



At the junction of the middle and lower thirds of this border may 

 be telt, by the application of pressure, the external division of the 

 maxillo-muscular artery, and lower down the angle of the jaw is 

 found to be very prominent in the horse. 



The region of the poll should be examined, the seat of that trouble- 

 some affection " poll-evil." The anterior and external borders of the 

 wing of the atlas stand out very prominently, and are easily felt in the 

 living animal to form a well-marked curve, the convexity of which 

 is directed downwards and forwards. These two edges are therefore 

 continuous with one another. But the upper surface of the wing is 

 clothed by muscle (the superior and inferior oblique muscles of the 

 head). In ill-nourished animals behind the occipital crest may be felt 

 the anterior extremity of the funicular division of the ligamentum 

 nuch-cE. In well-nourished animals, however, there is a considerable 

 quantity of fat in this region. 



