CONSTRICTOR MUSCLES. 



125 



are directed backwards from the pterygoid plate; and above it the levator 

 palati muscle p is seen. The lower border is overlaid by the middle con- 

 strictor muscle. The attachment to the pterygo-maxillary ligament cor- 

 responds with the origin of the buccinator muscle I. 



Fig. 28. 



Muscles : 



A. Inferior constrictor. 



B. Middle constrictor, 

 c. Upper constrictor. 

 D. Stylo-pharyngeus. 

 F. Levator palati. 



H. Teusor palati. 

 i. Buccinator. 

 K. Hyo-glossus. 



Nerves : 



1. Glosso-pharyngeal. 



2. Hypo-glossal. 



3. Superior laryugeal. 



4. External laryngeal. 



5. Recurrent laryugeal. 



6. Gustatory nerve. 



E\TER\AT, VIEW OF THE PHARYNX (Illustrations of Dissections). 



Action of constrictors. The muscles of both sides contracting will 

 diminish the size of the pharynx; and as the anterior attachments of the 

 lower muscles are nearer together than those of the upper, the tube will 

 be contracted more behind the larynx than near the head. 



In swallowing the morsel is seized first by the middle constrictor, and 

 is delivered over to the inferior, by which it is conveyed to the oesopha- 

 gus: both muscles act involuntarily. By the contraction of the upper 

 muscle the space above the mouth will be narrowed, so that the soft palate 

 being raised, the upper portion of the pharyngeal space can be shut off 

 from the lower. 



