PHARYNX AND LARYNX. 45 



3. The Pharynx is the continuation backward of the 

 buccal cavity beyond the soft palate. The nasal cavity 

 also opens into it above the palate. To expose it 

 better the symphysis of the mandibles may be cut 

 through, allowing one side of the lower jaw to be de- 

 pressed. 



a. The Epiglottis is the conspicuous V-shaped 

 lobe of cartilage projecting into the pharynx. 



b. The Glottis, or Rima Glottidis. Posteriorly 

 the pharynx ends in two openings. One of these is 

 slit-like and placed ventrally ; the inconspicuous folds 

 bounding it ar^ the false vocal cords, while immedi- 

 ately below or posterior to these are two more dis- 

 tinct folds, the true vocal cords. The slit between the 

 true cords is the glottis ; it leads into the larynx. The 

 epiglottis projects over this opening and covers it 

 during the act of swallowing. 



c. The Oesophagus. The second opening at the 

 posterior of the pharynx is the beginning of the 

 oesophagus. It lies dorsal to the glottis. 



d. The Eustachian Tubes. Slit open the soft 

 palate. The openings of the Eustachian tubes will be 

 seen in the anterior portion of the dorsal wall of the 

 pharynx, on a level with the nasal cavity. 



To expose the nasal cavity insert the blade of the 

 scissors into the anterior nares of one side and cut 

 back close to the septum, tising the bone forceps if 

 necessary. Remove also the external wall of this side 

 of the nasal cavity. The structure of this side is de- 

 stroyed, but now by carefully removing as much of 

 the septum as possible the nasal chamber of the other 

 side will be exposed. 



4. The Nasal Cavity. Note the arrangement of 

 the turbinate bones. The respiratory passage lies 



