364 



ELEMENTARY PHYSIOLOGY 



delicate filaments, the olfactory nerves, which are distri- 

 buted as follows (Fig. 115) :— 



On each wall of the septum the mucous membrane 

 forms a fiat expansion, but on the side walls of each nasal 

 cavity it follows the elevations and depressions of the 

 inner surfaces of what are called the upper and middle 

 turbinal, or spongy bones. These bones are called 



S/i. FL 



Fio. 116.— A Transverse and Vertical Section of thb Osseous Walls 

 OF THE Nasal Cavity taken nearly through the letter / in the 



FOREGOING FIGURE. 



Cr. the cribriform plate ; S.T, M.T, the chambered superior and middle 

 turbinal bones on which and on the septum (*.;).) the filaments of the 

 olfactory nerve are distributed ; I.T, the inferior turbinal bono ; I'/, the 

 palate; An. the an^niHi. or chamber which occupies the greater part of 

 the maxillary bone and opens into the nasal cavity. 



spongy because the interior of each is occui)ied by air 

 cavities separated from each other by very delicate 

 partitions only, and coiumuuicating "with the nasal 

 cavities. Hence the bones, though massive-looking, are 

 really exceedingly light and delicate, and fully deserve 

 the appellation of spongy (Fig. 116). 



Over these upper and middle turbinal bones, and on 



