DISSECTION OF THE HEAD AND NECK 293 



(ca) Pterygopharyngeal muscle (M. pterygopharyngeus). 



(cb) Buccopharyngeal muscle (M. buccopharyngeus). 



(cc) Mylopharyngeal muscle (M. mylopharyngeus) . 



(cd) Glossopharyngeal muscle (M. glossopharyngeus). 

 Between (b) and (c) observe the M. stylopharyngeus and the N. 



glossopharyngeus. Observe the interval between the uppermost con- 

 strictor muscle and the base of the skull; here a thickened portion of 

 the tela submucosa pharyngis (0. T. pharyngeal aponeurosis), called 

 the pharyngobasilar fascia (fascia pharyngobasilaris) , is visible. The 

 semilunar space where the muscle is absent is sometimes called the 

 " sinus of Morgagni." In the lateral part of this on each side the M. 

 levator veli palatini, the M. tensor veli palatini, and the cartilage of 

 the Eustachian tube (cartilago tubae auditivae) can be seen; these 

 structures will be dissected out carefully later. 



Cavity of Pharynx (Cavum pharyngis). 



Open the pharynx from behind by a vertical incision in the 

 median line of its posterior wall along its whole length. Divide 

 the fascia pharyngobasilaris close to the basis cranii externa 

 on each side, carrying the knife from the median line lateralward 

 as far as the cartilage of the Eustachian tube. Remove the stuff- 

 ing of tow or cotton. Sponge the tunica mucosa clean and study 

 the cavum pharyngis. With what cavities or tubes does the 

 cavity of the pharynx communicate? Explore the " vault of 

 the pharynx " (fornix pharyngis). How is the cavity of the 

 pharynx bounded ? What very important structures are related 

 to its lateral walls? Where does the pharynx end and the 

 oesophagus begin? Observe the three parts of the cavum 

 pharyngis (see Fig. 125) : 



(a) Nasal part (pars nasalis) (0. T. nasopharynx). 



(b) Oral part (pars oralis) (0. T. oral pharynx). 



(c) Laryngeal part (pars laryngea) (0. T. laryngopharynx). 

 Find - 



(d) Pharyngeal opening of Eustachian tube (ostium pharyngeum 



tubae auditivae}. 



(da) Anterior lip (labium anterius). 



(db) Posterior lip (labium posterius). This is sometimes called 



the tubal projection (torus tubarius), owing to the 

 rounded eminence it forms. 



(dc) Salpingopharyngeal fold (plica salpingopharyngea) . 



It extends downward from the lower end of the labium 

 posterins. 



(e) Pharyngeal recess of Rosenmiiller (recessus pharyngeus [Rosen- 



mulleri]) (0. T. recessus infundibuliformis). 



(/) Pharyngeal tonsil (tonsilla pharyngea) (0. T. Luschka's tonsil). 

 It is enlargement of this tonsil that constitutes the " post- 

 adenoids" so often met with in children. 

 (fa) Tonsillar crypts (fossulae tonsillares). 



