232 



ANATOMY AND PHYSIOLOGY 



surfaces in the median line. Each lateral surface terminates below 

 in the wing of the nose ala nasi. The alae are flexible and move- 

 able. The part that is supported by the nasal bones is the bridge 

 of the nose. The nostrils are the expanded portion; they contain 

 no bones, but small plates of cartilage instead, which are moved by 

 little muscles, therefore, they may be expanded or contracted. 



Immediately within the margins of the nostrils are the vestibules; each 

 vestibule terminates within the tip of the nose in a small pouch, the ventricle. 

 The nostrils and vestibules of the right and left sides are separated by thin 

 cartilages forming a mobile septum (columna). 



JJ 



FIG. 155. NASAL CAVITY AND NASO-PHAEYNX. (From Leaver's Surgical Anatomy.) 

 __ b, Superior turbinal; a, superior meatus; c, middle turbinal; s, middle meatus; d, 

 inferior turbinal; e, inferior meatus; g, i,j, tongue; k, hyoid bone; p, q, r, sphenoid 

 bone and sphenoidal sinus; /, naso-pharynx; t>, hard palate (floor of nose). 

 L_ The remaining references are explained in another chapter (p. 136). 



Their internal margins are provided with stiff hairs to arrest 

 particles of foreign substance in the inspired air. 



The cavity of the nose is divided into the right and left cavities 



