260 THE ORGANS OF DIGESTION 



purposes of studying, divided into a nasal, oral, and 

 laryngeal portion. 



The nasal part or nasopharynx, lies posterior to the 

 nares and above the soft palate.' In front are the 

 posterior nares (choanae); behind, the pharyngeal 

 tonsil, consisting of lymphoid tissue seen above the 

 orifices of the Eustachian tubes in the median line. 

 The floor of the nasopharynx is continuous with the 

 nasal fossae, anteriorly, and behind is the sloping 

 portion of the soft palate. On its lateral wall is the 

 orifice of the Eustachian tube, level with the inferior 

 turbinated bone and one-third to one-half inch pos- 

 terior. 



The oral part extends from the soft palate to the 

 level of hyoid bone. It opens into the oral cavity, 

 through the fauces, bounded on either side by the 

 anterior and posterior pillars, between which are the 

 tonsils. 



The laryngeal part is continuous with the oral 

 portion above, and below at the level of the cricoid 

 cartilage is^continuous with the esophagus. Anteriorly, 

 it presents the aperture of the larynx, bounded in 

 front by the epiglottis, and laterally by the aryteno- 

 epiglottic folds. 



The pharynx is lined with mucous membrane 

 continuous with that lining the Eustachian tube, the 

 nasal fossae, the mouth, and the larynx. In the naso- 

 pharynx it is covered by stratified ciliated epithelium; 

 in the oral and laryngeal portions it is of the 

 stratified squamous variety. 



THE ESOPHAGUS (GULLET) 



The esophagus is the tube connecting the pharynx 

 with the stomach, and extends from the level of the 

 sixth cervical vertebra through the diaphragm, entering 

 the stomach opposite the tenth or eleventh dorsal 



