. PHARYNX 287 



part of the space, close to the base of the skull and between 

 the origin of the two muscles, the auditory tube (O.T. 

 Eustachian tube] can be defined. 



Pharyngeal Aponeurosis. The upper part of the pharyn- 

 geal aponeurosis is strong, and it maintains the integrity of 

 the wall of the pharynx where the muscular fibres of the 

 superior constrictor are absent. As it passes downwards it 

 gradually becomes weaker, until it is ultimately lost as a 

 distinct layer. It lies between the muscles and mucous 

 membrane and is visible, from the outside of the pharynx, 

 only where the muscles are absent. It is the principal means 

 by which the pharynx is attached to the base of the skull, 

 and it is united also to the auditory tubes and the bony 

 margins of the choancz. 



Dissection. The pharynx must now be opened by a vertical 

 median incision through the entire length of its posterior wall. 

 At the upper extremity of the cut, the knife should be carried 

 transversely, close to the base of the skull. The stuffing must 

 then be removed and the mucous surface of the pharynx cleansed. 



Interior of the Pharynx. The mucous membrane is now 

 exposed, and it should be noted that it is continuous, 

 through the various apertures which open into the pharynx, 

 with the mucous membrane of the nasal cavities, the auditory 

 tubes and tympanic cavities, the mouth proper, the larynx, and 

 the o&sophagus. 



Racemose glands, which lie immediately subjacent to the 

 mucous membrane and secrete mucus, are present in great 

 numbers. There are also numerous lymph follicles, and 

 in certain localities they are aggregated together into large 

 masses (the palatine tonsils and the pharyngeal tonsil), 

 which will be studied with the regions of the pharynx in 

 which they are placed. 



The soft palate projects into the pharynx, posterior to 

 the isthmus faucium, and divides the cavity of the pharynx 

 into an upper and a lower part. -The upper part, called 

 the naso - pharynx, communicates with the nasal cavities 

 and the tympanic cavities by four apertures, viz. the two 

 choanae (O.T. posterior nares) -and the two auditory tubes 

 (O.T. Eustachian tubes). 



The lower portion of the pharynx may be regarded as 

 consisting of an oral part, which lies posterior to the 

 mouth and tongue, and a laryngeal part, placed posterior 



