6o THE SURGICAL ANATOMY OF THE HORSE 



above operation, or from some other cause, such as external injury, it 

 will be easily diagnosed by the ejection of saliva, which takes place at 

 every movement of the jaw. Siiould the fistula be on the side of the 

 face the position is very favourable for treatment. An incision should 

 be made along the line of direction of the duct and over the seat of the 

 fistula. Having thus exposed the duct the edges of the rent aperture 

 should be pared and the opening closed in the manner described above 

 for the removal of a salivary calculus. 



The Submaxillary Gland 



This gland is much more deeply seated than the parotid, and in 

 consequence is much less liable to injury from without. It lies to the 

 side of the larynx in the inter-maxillary space, and outwardly it is 

 protected by the ramus of the inferior maxilla. It is smaller than the 

 parotid, and in shape it is somewhat crescentic, with its concave border 

 directed upwards and forwards. 



The gland is loosely attached superiorly beneath the wing ot the 

 atlas, and it extends downwards and forwards to the inter-maxillary space 

 between the internal pterygoid and the thyro-hyoid muscles. Its 

 anterior border is thin, and margined in its superior portion by the 

 upper belly of the digastricus muscle and inferiorly to this by the 

 Duct of Wharton, which is the excretory duct of the gland. 



The nerve-supply to this gland is derived from the carotid plexus, 

 wliilst its blood-supply comes from small twigs given off" by the external 

 carotid and submaxillary arteries. 



Ranula 



This term is applied to an acute inflammation of the submaxillary 

 gland and its excretory duct. It is commonly met with in cattle and 

 occasionally also in horses. There is considerable swelling of the gland 

 and the duct, the orifice of the latter being frequently occluded by 



