668 



DISSECTION OF THE NOSE. 



the middle turbinate bone ; below this the outer wall recedes, form- 

 ing the respiratory passage, which has a width near the floor of about 



Openings, three-fifths of an inch. In front, each fossa opens on to the face, and 

 behind into the pharynx, by orifices called nares. Other apertures 

 in the roof and outer wall lead into air-sinuses in the surrounding 

 bones, viz., frontal, ethmoid, sphenoid, and superior maxillary. 

 Each fossa presents for examination a roof and floor, an inner and 

 outer wall, and an anterior and posterior opening. 



Roof. The ROOF is strongly arched from before backwards, and is formed 



by the cribriform plate of the ethmoid bone in the centre ; by the 

 frontal and nasal bones, and the lateral cartilages in front ; and by 

 the body of the sphenoid, and the sphenoidal spongy bone, and the 



Floor. 



Inner 

 boundary 



sup. turt. tone 

 mid. etkm. cell 



FIG. 235. THE NASAL Foss^: IN CORONAL SECTION. 



On the right side of the figure the section passes through the openings of 

 the middle ethmoidal cells and the antrum into the middle meatus : on the 

 left side, a section of the hinder part of the fossa is represented, and the 

 posterior ethmoidal cells are seen opening into the superior meatus. 



palate bone, at the posterior part. In the dried skull many 

 apertures exist in it ; most are in the ethmoid bone for the 

 branches of the olfactory nerve with vessels, and one for the nasal 

 nerve and vessels ; on the front of the body of the sphenoid is the 

 opening of its sinus. 



The FLOOR is slightly hollowed from side to side, and is formed by 

 the palate processes of the superior maxillary and palate bones. 

 Near the front in the dry skull is the incisor foramen leading to the 

 anterior palatine fossa. 



The INNER WALL (septum nasi) is partly osseous and partly cartila- 

 ginous. The osseous part is constructed by the vomer, by the 

 perpendicular plate of the ethmoid bone, and by those parts of the 

 frontal and nasal with which this last bone articulates. The 



