32 SURGICAL ANATOMY OF THE 



the nostril with the concavity downwards, then pushed 

 backwards by the side of the septum until the mucous 

 membrane of the back of the pharynx is reached ; next 

 it is to be slightly withdrawn, and rotated between the 

 fingers, so as to bring its point upwards and outwards, 

 which may be known to be in the orifice of the tube 

 when it cannot be made to rotate easily. 



The mucous membrane lining the nares completely 

 covers the surfaces of the above-mentioned bony parts, 

 terminating in front at its juncture with the skin. In 

 color it is red, and its superior surface is studded with 

 orifices of glands which secrete mucus. It is of variable 

 thickness, and is very thin where it is prolonged into 

 the several sinuses. It is thickest on the septum, espe- 

 cially so at its anterior half. It is moderately thick on 

 the roof of the fossa, where it invests the proper bones 

 of the nose and the cribriform plate of the ethmoid ; it 

 enters the sphenoidal sinus, and becomes very thin. It 

 covers the anterior ethmoidal cells and the superior 

 spongy bones ; it sinks into the groove separating this 

 bone from the sphenoidal sinus, and closes the spheno- 

 palatine canal ; and so it may be traced over each por- 

 tion of the bony and cartilaginous structure to be con- 

 tinuous behind with the pharyngeal membrane and with 

 the skin of the face in front. 



Arteries. This membrane is supplied by the spheno- 

 palatine branch of the internal maxillary, which divides 

 into two branches; the more internal being distributed 

 to the septum, divides and passes towards the anterior 

 palatine foramen ; the external is distributed to the 

 external parietes, and subdividing supplies the meatuses 

 and spongy bones. 



