THE NASO-PHARYNX 329 



THE NASO-PHARYNX 



The naso-pharynx lies behind the nasal cavity and 

 constitutes the highest part of the pharynx. In front, it 

 communicates with the nasal cavity through the choanae 

 (posterior nares), which are each one inch long and half an 

 inch wide. Below, it communicates freely with the oral part 

 of the pharynx, but this communication is closed when the 

 soft palate is raised (p. 97). 



The pharyngeal orifice of the auditory (Eustachian) tube is 

 situated on the side wall of the naso-pharynx. Behind the 

 orifice, the cartilage which supports the roof and medial wall 

 of the tube forms a distinct prominence, termed the torus 

 tubarius (Eustachian cushion), and this elevation forms the 

 anterior wall of a small pocket of mucous membrane which 

 constitutes the pharyngeal recess (fossa of Rosenmiiller). 



The auditory tube passes backwards and laterally from the 

 pharynx to the tympanum, and, as it is kept patent by the 

 cartilage in its wall, it affords a channel for the constant 

 renewal of the air in the tympanic cavity (p. 201). When the 

 tube becomes obstructed, the air within the tympanum 

 becomes absorbed and deafness results. Under certain 

 conditions it is desirable to inflate the tympanic cavity, and 

 this operation is conducted through the auditory tube. A 

 Eustachian catheter is passed backwards along the floor of the 

 inferior meatus of the nose until it impinges against the 

 posterior wall of the naso-pharynx. If the instrument is then 

 rotated laterally through 90, its point will rest in the pharyngeal 

 recess. It is then withdrawn slightly, and the point can be felt 

 to slip over the torus tubarius and enter the pharyngeal orifice 

 of the tube. 



The posterior wall of the naso-pharynx contains a small 

 collection of lymphoid tissue, which is termed the pharyngeal 

 tonsil. After puberty the pharyngeal tonsil rapidly atrophies, 

 but before that period it may be of considerable size. In 

 children this lymphoid tissue frequently proliferates and gives 



