THE SURGICAL ANATOMY OF THE HORSE 



(2) The anterior auricular artery runs upwards on the 



capsular ligament of the temporo-maxillary joint to reach 



the anterior aspect of the base of the external ear, to which 



it is distributed. 



B. The Internal Maxillary Artery passes to the inner side 



of the condyle of the lower jaw, and crosses the guttural pouch 



obliquely. Whilst crossing the pouch it forms an S-shaped 



curve, the first convexity of which is directed downwards. The 



artery now enters the subsphenoidal canal above the root of the 



subsphenoidal process. It passes through the whole length of 



rhe canal, and leaving it by the foramen rotundum, it takes 



its course to the maxillary hiatus, where it is continued as the 



palato-labial artery. The branches given off by the internal 



maxillary artery are as follows : 



(i) The inferior dental artery. — This is a vessel of con- 

 siderable calibre, which is given off from the first convexity 

 of the S-shaped curve. It passes between the two 

 pterygoid muscles, and then between the internal pterygoid 

 and the surface of the inferior maxilla. It next enters the 

 inferior dental canal, and is distributed to the molar and 

 incisor teeth of the lower jaw. Whilst in the canal it gives 

 off a small mental branch, which passes out through the 

 mental foramen to anastomose with the inferior labial artery 

 as already stated. 



(2) The tympanic artery comes off from the opposite side 

 of the internal maxillary artery. It follows the course of 

 the chorda tympani nerve, and passes into the petrous 

 temporal bone to supply the tympanum or middle ear. 



(3) The great meningeal artery. — This branch passes into the 

 cranial cavity through the outermost notch in the superior 

 border of the wing of the post-sphenoid bone, to anastomose 

 in the parieto-temporal canal with the mastoid artery. 



