562 THE ARTERIES. 



The pterygoid branches, irregular in their number and origin, supply the 

 Pterygoid muscles. 



The masseteric is a small branch which passes outward, above the sigmoid 

 notch of the lower jaw, to the deep surface of the Masseter. It supplies that 

 muscle, and anastomoses with the masseteric branches of the facial and with the 

 transverse facial artery. 



The buccal is a small branch which runs obliquely forward between the Internal 

 pterygoid and the ramus of the jaw, to the outer surface of the Buccinator, to 

 which it is distributed, anastomosing with branches of the facial artery. 



BRANCHES OF THE THIRD OR SPHENO-MAXILLARY PORTION OF INTERNAL 



MAXILLARY. 



Alveolar. Vidian. 



Infra-orbital. Pterygo-palatine. 



Posterior or Descending Palatine. Naso- or Spheno-palatine. 



The alveolar or posterior dental branch is given off from the internal maxillary 

 by a common branch with the infra-orbital, and just as the trunk of the vessel is 

 passing into the spheno-maxillary fossa. Descending upon the tuberosity of the 

 superior maxillary bone, it divides into numerous branches, some of which enter 

 the posterior dental canals, to supply the molar and bicuspid teeth and the lining 

 of the antrum, and others are continued forward on the alveolar process to supply 

 the gums. 



The infra-orbital appears, from its direction, to be the continuation of the trunk 

 of the internal maxillary. It arises from that vessel by a common trunk with the 

 preceding branch, and runs along the infra-orbital canal with the superior maxil- 

 lary nerve, emerging upon the face at the infra-orbital foramen, beneath the Levator 

 labii superioris. Whilst contained in the canal, it gives off branches which ascend 

 into the orbit, and supply the Inferior rectus and Inferior oblique muscles and the 

 lachrymal gland. Other branches (anterior dental) descend through canals in 

 the bone to supply the mucous membrane of the antrum and the front teeth of 

 the upper jaw. On the face some branches pass inward toward the nose, anasto- 

 mosing with the angular branch of the facial artery and nasal branch of the 

 ophthalmic ; and other branches descend beneath the Levator labii superioris and 

 anastomose with the transverse facial and buccal branches. 



The four remaining branches arise from that portion of the internal maxillary 

 which is contained in the spheno-maxillary fossa. 



The descending palatine passes down the posterior palatine canal with the 

 anterior palatine branch of Meckel's ganglion, and, emerging from the posterior 

 palatine foramen, runs forward in a groove on the inner side of the alveolar border 

 of the hard palate to the anterior palatine canal, where the terminal branch of the 

 artery passes upward through the foramen of Stenson to anastomose with the 

 naso-palatine artery. Its branches are distributed to the gums, the mucous 

 membrane of the hard palate, and the palatine glands. Whilst it is contained in 

 the palatine canal it gives off branches, which descend in the accessory palatine 

 canals to supply the soft palate and tonsil, anastomosing with the ascending 

 palatine artery. 



The Vidian branch passes backward along the Vidian canal with the Vidian 

 nerve. It is distributed to the upper part of the pharynx and Eustachian tube, 

 sending a small branch into the tympanum, which anastomoses with the anterior 

 tympanic. 



The pterygo-palatine is also a very small branch, which passes backward 

 through the pterygo-palatine canal with the pharyngeal nerve, and is distributed 

 to the upper part of the pharynx and Eustachian tube. 



The spheno-palatine passes through the spheno-palatine foramen into the 

 cavity of the nose, at the back part of the superior meatus, and divides into two 

 branches : one internal, the naso-palatine or superior artery of the septum, passes 



