406 HEAD AND NECK 



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 anteriorly 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 ; which spring from the descend- 

 ing palatine, 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 tonsil. 



The Spheno-palatine Artery. 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 posteriorly to the upper part of the 

 pharynx 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 ; this 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 of the vomer ; 

 it anastomoses with the great palatine artery, and with the 

 septal branch of the superior labial artery. 



THE LARYNX. 



The lateral portions of the mandible, which are still 

 attached by mucous membrane to the sides of the tongue, 

 should be removed, and the dissection of the larynx com- 

 menced. 



