THE SENSE OF SMELL 



395 



The Nasal Fossae or Cavities. These are two 

 bony cavities separated by a vertical wall, formed by 

 the perpendicular plate of the ethmoid, the vomer, 

 and the triangular cartilage. The bony walls are 

 lined with mucous membrane. On the outer wall 



PROBE 

 SINUS 



FIG. 139 



'* 



H 



OPENINGS OF POSTERIOR 

 ETHMOIDAL CELLS 



SPHENOIDAL 

 SINUS 



External wall of right nasal fossa, parts of the turbinates having been 

 cut away to show the orifices of the sinuses which open into the meatuses. 

 (Testut.) 



each cavity communicates by means of foramen and 

 fissures with the sphenoid, frontal sinuses, the antrum 

 of Highmore, and ethmoid cells, and receives on 

 its floor the opening of the tear-duct from the 



