OF THE CAVITIES OF THE NOSE. 449 



When inspiration takes place with great force, the alae nasi 

 would be pressed against the septum, if they were not drawn 

 out and dilated by some of the muscles above mentioned. 



Of the Cavities of the Nose. 



To the description of the osseous parts of the nasal cavities 

 in page 89, it ought now to be added, that the vacuity in the 

 anterior part of the osseous septum is filled up by a cartilaginous 

 plate, connected with the nasal lamella of the ethmoid bone 

 above, and with the vomer below. This plate sends off those 

 lateral portions already described, which form the cartilaginous 

 part of the bridge of the nose. 



It should also be observed that at the back parts of these 

 cavities are two orifices called the Posterior Nares, (see 

 fig. 118, p. 454,) which are formed by the palate bones, the 

 vomer, and the body of the sphenoidal bone, and are somewhat 

 oval. 



The nasal cavities, thus constructed, are lined by a peculiar 

 membrane, which is called pituitary from its secretion of mucus, 

 or Schneiderian after the anatomist who described it with ac- 

 curacy.* 



This membrane is very thick and strong, and abounds with 

 so many blood-vessels, that in the living subject it is of a red 

 color. It adheres to the bones and septum of the nose like 

 the periosteum, but separates from them more easily. The 

 surface which adheres to the bones has some resemblance to 

 periosteum, while the other surface is soft, spongy, and rather 

 villous. Bichat seems to have considered this membrane as 

 formed of two lamina, viz. periosteum, and the proper mucous 

 membrane ; but he adds, that it is almost impossible to separate 

 them. 



It has been supposed that many distinct glandular bodies 

 were to be seen in the structure of this membrane by examin- 

 ing the surface next to the bones ;f but this opinion is adopted 



* Conrad Schneider, a German professor, in a large work, "De Catarrhis," 

 published about 1660. 

 f See Winslow, Section X. No. 337. 



38* 



