HEAD AND NECK OF THE HORSE 127 



While within the alar canal, the internal maxillary furnishes two 

 branches, the anterior deep temporal and the ophthalmic arteries, which 

 very commonly arise by a common stem. 



(1) A. temporalis profunda anterior, — The anterior deep, temporal 

 artery leaves the alar canal by the small alar foramen, and at once 

 buries itself underneath the temporal muscle, where its branches anas- 

 tomose with those of the posterior artery of the same name. 



(2) A. opJithalmica. — The ophthalmic artery leaves the canal in 

 company with the parent vessel, and thus gains the orbit, where its 

 course and distribution have been examined (page 114). 



The third part of the internal maxillary artery passes along the 

 pterygo-palatine fossa from the anterior alar foramen to the vicinity of 

 the posterior palatine foramen, into which it is continued as the greater 

 palatine artery. This part of the vessel is very intimately related to 

 the maxillary nerve and its branches. It supplies the following 

 branches : — 



(1) A. buccinatoria. — The buccinator artery rises close to the 

 anterior alar foramen, and runs to the cheek on the lateral face of the 

 maxillary tuber. It furnishes branches to the masseter and pterygoid 

 muscles, and, as has been already noted, to the component structures of 

 the cheek (page 51). 



(2) A. infraorhitalis. — The infraorbital artery runs direct to the 

 maxillary foramen, by which it enters the infraorbital canal. Its 

 subsequent course and distribution will be considered later. Usually 

 the infraorbital gives origin to the malar artery (a. malaris), though 

 occasionally this leaves the internal maxillary itself Whichever may 

 be its origin, the malar artery passes along the ventral wall of the orbit 

 (outside the periorbita), crosses the orbital rim and ends on the face by 

 anastomosing with the angular artery of the eye. Small branches are 

 supplied to the inferior oblique muscle, the lachrymal sac and the 

 lower eyelid. 



(3) A. palatina mAnor. — The lesser palatine artery is a small 

 vessel that gains the soft palate by crossing the medial surface of the 

 maxillary tuber, 



(4) A. sphenopalatina. — The spheno-palatine artery enters the 

 spheno-palatine foramen immediately, in order to gain the cavity of 

 the nose. 



(5) A. palatina major. — The greater palatine artery, the direct 

 continuation of the internal maxillary, traverses the palatine canal and 

 supplies the hard palate. 



N. MAXILLARIS. — The maxillary nerve is one of the divisions of the 



