THE PHARYNX 



1129 



the internal jugular vein, the sympathetic and the last four cranial nerves. 

 Anteriorly, it communicates above with the nasal cavity, beneath this with the 

 oral cavity, and below with the laryngeal cavity. The pharynx is correspondingly 

 divided into three parts: the nasal pharynx [pars nasalis], which is exclusively 

 respiratory in function; the oral pharynx [pars oralis], which is both respiratory 

 and alimentary; and the laryngeal pharynx [pars laryngea], which is almost 

 entirely alimentary. 



Size and form. — ^The average length of the pharynx is about 12 cm. (5 

 inches). It is widest at the nasal pharynx, with a constriction (isthmus) connect- 



(Sobotta-McMurrich.) 



Fig. 888. — The Interior of the Pharynx, Viewed from Behind. 



Pharyngeal tonsil geptum 



Torus tubarius 



Pharyngeal recess t » y^a \\< 



Soft palate 



Glossopalatine arch '^~^* 



Styloid process 



— j — Styloid muscles 



Salpingopharyngeal 



/ %-^J~~P fold 

 .. // u i Parotid gland 

 r/i '4 / 



t/f ^ 'J—f— Pharyngopalatine arch 



f ;// 



Palatine tonsil 



Pharyngo-epiglottic fold 



Aditus laryngis 



Cuneate tubercle 



Corniculate tubercle 



Fold of laryngeal nerve 



Thyreoid gland 



(Esophagus 



ing it with the widened oral pharynx, and is again somewhat narrowed'at the junc- 

 tion of oral and laryngeal pharynx (fig. 888). It is narrowest at the point where 

 it joins the oesophagus below. In sagittal section (fig.^848), it is evident that the 

 anterior and posterior walls are closely approximated in the larjmgeal pharynx, 

 and have only a small space between them in the oral pharynx. The nasal 

 pharynx, however, has a considerable antero-posterior depth, and by its bony 

 walls is always kept open for respiratory purposes. 



Structure, — The pharynx approaches the typical structure of the ahmentary canal, j'et 

 differs from it in several important respects. The lining mucosa is continuous with that of the 

 various cavities which open into the pharynx. Above, it is closely adherent to the base of the 

 cranium, where it is thick and dark in colour. It becomes thinner where it approaches the open- 

 ings of the auditory tubes and choanee; and below it is paler and thrown into longitudinal folds. 

 The epithelium of the greater part of the nasal pharynx (from the orifice of the auditory tube 

 upward) is stratified ciliated columnar, while that of the remainder of the pharynx is stratified 

 squamous. 



