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 Eustachian 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 ; inferiorjy, behind the root of the tongue, is 

 the opening of the larynx, and behind this the cesojyhagus. 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 median 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-pharyngeiis. 



Hyo-pharyngens, 



Thyro-pharyngeus. 



Crico-pharyngeus. 



Aryteno-pliaryngeus. 

 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 froin the inner aspect of the hyoid cornu, 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. 



