PHARYNGEAL MUSCLES. 297 



the cranium by muscles and aponeurosis, infero-laterally to the 

 larynx, and infero-posteriorly it is continuous with the oesophagus. 

 It communicates with other cavities by seven openings — viz., the 

 two posterior nares superiorly ; posteriorly, on either side, with the 

 slit-like openings of the Eizstachian tubes, which lead to the 

 guttural pouches, and are guarded by a cartilaginous valve ; 

 anteriorly, below the posterior nares, is the isthmus of the fauces, 

 leading into the mouth, and, excepting during deglutition, closed 

 by the velum palati ; inferiorly, behind the root of the tongue, is 

 the opening of the larynx, and behind this the oesophagus. The 

 walls of the pharynx consist of a muscular layer, with a lining of 

 mucous membrane. 



PHARYNGEAL MUSCLES. 



The muscular layer of the pharynx is separable into seven pairs 

 of muscles. These are best seen posteriorly, where they appear 

 as a series of flattened, fleshy bands, the superior of which meet 

 their fellows of the opposite side at a mesian vertical line or raphe. 

 The names of the muscles are as follows, and, excepting the first 

 and last, they are named in order from above downwards : — 



Pharyngo-staphylinus. 



Pterygo-pharyngeus. 



Kerato-pharyngeus.. 



Hyo-pharyngeus. 



Thyro-pharyngeus. 



Crico-pharyngeus. 



Aryteno-pharyngeus. 

 PHARYNGO-STAPHYLINUS. 



(See Muscles of the soft palate.) 



PTERYGO-PHARYNGEUS. 



(Fig. 90. I) 



This is a thin, broad band of muscle arising^ from the pterygoid 



process. Its fibres are directed backwards and downwards. It 



terminates by meeting its fellow at the posterior median line of 



the pharynx, of which cavity it is a constrictor. 



KERATO-PHARYNGEUS. 

 (Fig. 90. m.) 

 Arising from the inner aspect of the hyoid comu, this muscle, 

 A small, narrow band, runs inwards and downwards to the wall of 

 the pharynx, becoming blended with the pterygo-pharyngeus. It 

 is a levator, and by some considered a dilator of the pharynx. 



