NASAL FOSSAE 



91 



Fig. 42.* 



Palate processes of superior maxillary. 

 Palate processes of palate bone. 



nasal fossa is divided into three irregular longitudinal passages, 

 or meatuses, by three processes of bone, which project from its outer wall, 

 the superior, middle, and inferior turbi- 

 nated bones; the superior and middle 

 turbinated bones being processes of the 

 ethmoid, and the inferior a distinct bone 

 of the face. The superior meatus occu- 

 pies 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 open- 



* A longitudinal section of the nasal fossoe made immediately to the right of the 

 middle line, and the bony septum removed in order to show the external wall of the 

 left fossa. 1. The frontal bone. 2. The nasal bone. 3. The crista galli process of the 

 ethmoid. The groove between 1 and 3 is the lateral boundary of the foramen caecum. 

 4. The cribriform plate of the ethmoid. 5. Part of the sphenoidal cells. 6. The basilar 

 portion of the sphenoid bone. Bones 2, 4, and 5, form the superior boundary of the 

 nasal fossa. 7, 7. The articulating surface of the palatine process of the superior maxil- 

 lary bone. The groove between 7, 7, is the lateral half of the incisive canal, and the 

 dark aperture in the groove the inferior termination of the left naso-palatine canal 

 8. The nasal spine. 9. The palatine process of the palate bone. a. The superior tur- 

 binated bone, marked by grooves and apertures for filaments of the olfactory nerve. 

 b. The superior meatus. c. A probe passed into the posterior ethmoidal cells, d. The 

 opening of the sphenoidal cells into the superior meatus. e. The spheno-palatine fora- 

 men. /. The middle turbinated bone, g, g. The middle meatus. h. A probe passed 

 into the infundibular canal, leading from the frontal sinuses and anterior ethmoid cells; 

 the triangular aperture immediately above the letter is the opening of the maxillary 

 sinus, i. The inferior turbinated bone, k, k. The inferior meatus. Z, I. A probe passed 

 up the nasal duct, showing the direction of that canal. The anterior letters g, k, are 

 placed on the superior maxillary bone, the posterior on the palate bone. m. The in- 

 ternal pterygoid plate, n. Its hamular process, o. The external pterygoid plate, p. The 

 situation of the opening of the Eustachian tube. q. The posterior palatine foramina. 

 r. The roof of the left orbit. *. The optic foramen, t. The groove for the last turn of 

 the internal carotid artery converted into a foramen by the development of an osseous 

 communication between the anterior and middle clinoid processes, v. The sella turcica. 

 t. The posterior clinoid process. 



