

NASAL FOSSAE. 



bone, for the passage of filaments of the orbital branch of the supe- 

 rior maxillary nerve ; anterior and posterior ethmoidal foramina in 

 the suture between the os planum and frontal bone, the former 

 transmitting the nasal nerve and anterior ethmoidal artery and 

 the latter the posterior ethmoidal artery and vein ; the opening of 

 the nasal duct; and the supra-orbital notch or foramen, for the 

 supra-orbital nerve and artery. 



NASAL FOSS.ZE. 



The nasal fossa? are two irregular cavities, situated in the middle 

 of the face, and extending from before backwards. They are 

 bounded above by the nasal bones, ethmoid, and sphenoid ; below 

 by the palate processes of the superior maxillary palate bones ; 

 externally by the superior maxillary, lachrymal, inferior turbinated, 

 ethmoid, palate, and internal pterygoid plate of the sphenoid ; and 

 the two fossa? are separated by the vomer and the perpendicular 

 lamella of the ethmoid. These may be more clearly expressed in 

 a tabular form : 



Nasal bones. 

 Ethmoid. 

 Sphenoid. 



3 S^g 



*-. ~C . r 3 .2 

 O O gfX, o, 



rj co .x , 



a 1 *B 



02 M 



Palate processes of superior maxillary. 

 Palate processes of palate bone. 



Each nasal fossa is divided into three irregular longitudinal pas- 

 sages, or meatuses by three processes of bone, which project from 

 its outer wall, the superior, middle, and inferior turbinated bones ; 

 the superior and middle turbinated bones being processes of the 

 ethmoid, and the inferior a distinct bone of the face. The superior 

 meatus occupies the superior and posterior part of each fossa ; it is 

 situated between the superior and middle turbinated bones, and has 

 opening into it three foramina, viz. the opening of the posterior 

 ethmoid cells, the opening of the sphenoid cells, and the spheno- 

 palatine foramen. The middle meatus is the space between the 

 middle and inferior turbinated bones ; it also presents three foramina, 

 the opening of the frontal sinuses, of the anterior ethmoid cells, 

 and of the antrum. The largest of the three passages is the in- 

 ferior meatus, which is the space between the inferior turbinated 

 bone and the floor of the fossa ; in it there are two foramina, the 



