SPHENO-PALATINE GANGLION 321 



maxillary artery breaks up into its terminal branches in the 

 pterygo-palatine fossa. They are 



1. Posterior superior alveolar (p. 174). 



2. The infra-orbital (p. 303). 



3. The descending palatine. 



4. The spheno-palatine. 



Arteria Palatina Descendens. The descending palatine 

 artery is a terminal branch of the internal maxillary artery. 

 As it descends, in the pterygo-palatine fossa, it gives off, usually, 

 the artery of the pterygoid canal, and, as it enters the pterygo- 

 palatine canal, several small palatine arteries spring from it ; 

 then it becomes the great palatine artery. The great palatine 

 artery descends through the great palatine foramen into the 

 hard palate ; there it runs forwards to reach the incisive 

 foramen, through which it passes into the nasal cavity to 

 anastomose with the posterior artery of the septum, which is 

 an offset of the spheno-palatine artery. 



The small palatine arteries spring from the descending pala- 

 tine, immediately before it becomes the great palatine artery, 

 in the upper part of the pterygo-palatine canal ; they descend 

 through the small palatine canals, and are distributed to the 

 soft palate, the palatine arches, and to the palatine tonsil. 



Arteria Spheno-palatina. The spheno-palatine artery 

 enters the nasal cavity through the spheno-palatine foramen. 

 It gives off (i) a branch to the sphenoidal air sinus, (2) a 

 branch which passes backwards through the pharyngeal canal 

 (O.T. pterygo-palatine artery) to be distributed to the roof of 

 the posterior part of the nasal cavity and to the roof of 

 the pharynx; that branch anastomoses with the ascending 

 pharyngeal artery. Then the spheno-palatine artery divides 

 into lateral and septal posterior nasal branches. The lateral 

 branches are distributed to the lateral wall of the nasal 

 cavity, where they anastomose with the branches of the 

 posterior and anterior ethmoidal arteries, and with the lateral 

 nasal branch of the external maxillary. They supply not 

 only the muco-periosteum of the lateral wall of the nasal 

 cavity, but also the muco-periosteum of the air sinuses which 

 open into the cavity. The posterior septal branch of the 

 spheno-palatine artery accompanies the posterior nasal septal 

 nerve along the surface ot the vomer ; it anastomoses with 

 the great palatine artery, and with the septal branch of the 

 superior labial artery. 



VOL. in 2] 



