Chap. VI.] NOSE AND NASAL CAVITIES. 77 



oculi. At the front part of the middle meatus the 

 infundibulum opens. Rhinolithes (stone-like masses 

 of calcareous matter, formed, as a rule, around foreign 

 substances) are most often found in the inferior 

 meatus. 



The width of the nasal floor is about half an inch, 

 or a little over. Its smooth surface greatly favours 

 the passage of instruments. 



The mucous membrane lining the nasal cavi- 

 ties varies in parts. It is very thick and vascular 

 over the turbinate bones and over the septum, while 

 over the nasal floor, and in the intervals between the 

 turbinate bones, it is very much thinner. . The mucous 

 membrane lining the various sinuses and the antrum 

 is conspicuously thin and pale. The membrane is pro- 

 vided with many glands, which are most conspicuous 

 over the lower and hinder parts of the outer wall, and 

 over the posterior and inferior parts of the septum. 

 These glands may be the subject of considerable hyper- 

 trophy. They are capable of providing also a very 

 copious watery secretion, which has, in some cases of 

 chronic coryza following injury, been so free as to be 

 mistaken for an escape of cerebro-spinal fluid. There 

 is also much adenoid, or lymphoid, tissue in the nasal 

 mucous membrane, which is the primary seat of the 

 chief scrofulous affections that invade this part. Over 

 the inferior turbinated bone the mucous membrane 

 is very thick, lax, and vascular, and when the seat of 

 chronic inflammation, it may present itself as a large 

 movable fold that has often been mistaken for a polyp. 

 From the comparatively lax attachment of the mucous 

 membrane of the septum to the parts beneath, it 

 happens that hsematomata (localised extravasations 

 of blood) are often met with beneath the septal 

 mucous membrane after a blow on the nose. 



Polypi are often met with in the nose. They 

 are of two kinds, the mucous or myxomatous polyp 



