THE NOSE OR ORGAN OF SMELL. 



forming the roof of the nostrils; below by the palatine 

 processes of the superior maxillary and palate bones, with a 

 FIG. in. portion of the velum palati, 



constituting the floor of 

 these fossee, as well as of 

 the nostrils; externally they 

 are bounded by the superior 

 maxillary, lachrymal, ceth- 

 moid, turbinated, and palate 

 bones, and the internal pter- 

 ygoid plate of the sphenoid; 

 internally they are separa- 

 ted, on the median line, by 

 the septum composed of the vomer, the nasal lamella of the 

 (Ethmoid, and the nasal cartilaginous septum. ' 



The outer wall is very irregular, being roughened by the 

 three turbinated, or spongy bones the superior, middle, 

 and inferior. These have spaces between them, known as 

 meatuses. As the space between the superior and middle 

 spongy bones is the superior meatus ; that between the 

 middle and lower is the middle meatus ; and that between 

 the lower and floor of the nostrils is the inferior meatus. 

 Into the superior meatus the posterior wthmoid cells and 

 sphenoid sinuses open. 



The middle meatus is the widest, and opens into the 

 antrum. In the dry bone this opening appears large; 

 while in the fresh state it will only admit a small probe, 

 being closed by a fold of the mucous membrane. It receives 

 the anterior cethmoid cells, and has in its front part a groove 

 called the infundibulum, which leads to the frontal sinus. 



FIG. Ill represents a vertical section of the Nasal Fossae. 1 Anterior 

 fossae of the cranium. 2 Dura mater, covering the fossae. 3 Dura mater 

 raised. 4 Cristagalli of aethmoid bone. 5 5 Cribriform plate. 6 Nasal lamel- 

 la. 7 7 Middle turbinated bones. 8 8 Ethmoid cells. 9 9 Os-planum. 10 10 

 Inferior turbinated, or spongy bones. 11 Vomer. 12 Superior maxillary bone. 

 13 Articulation of superior maxillary with the eethmoid. 14 Front wall of 

 the antrum. 15 Fibrous membrane of the antrum. 16 Mucous membrane of 

 antrum. 17 Palatine process of superior maxillary bone. 18 Roof of the mouth. 

 19 A section of the mucous membrane. 



