THE XOSE 897 



The anterior and posterior ethmoidal arteries derived from the ophthahnic 

 supi)ly the upper purtiuii i)t' tlie septum, tlic roof, the outer wall (anteriorly) and 

 the anterior and posterior ethmoidal cells. 



The descending palatine of the internal maxillary sends a few small hranches 

 to the back of tlie inferior meatus and lower turbinal bone. 



The Vidian and pterygo-palatine supply the l)ack part of the roof. 



The branch to the septum derived from the superior coronary of the facial 

 ramifies in the membrane covering its lower and front portion. 



The veins form a plexus in the mucous membrane, especially marked at the 

 lower and hinder portions of the fossa. The emissary trunks accompany the 

 arteries, the spheno-palatine joins the pterygoid plexus, the ethmoidal pass to 

 the ophthalmic vein but also have communications with the meningeal veins, and 

 the anterior part of the plexus is drained by veins which pass forwards to termi- 

 nate in the tributaries of the facial vein. 



Communications are formed with the veins within the cranial cavity, through 

 the cribriform foramina and foramen ceecum, and also with the facial vein through 

 small foramina in the nasal bone and nasal process of the maxilla. 



The lymphatics form a well-developed j^lexus, which communicates, through 

 the lymphatics surrounding the olfactory nerves, Avith the subdural space within 

 the cranial cavity, posteriorly with the j^haryngeal lymphatics, and anteriorly with 

 the lymphatics of the face. 



67 



