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PHARYNX. 61 



The CONSTRICTOR INFERIOR is the most superficial of the 

 three muscles; it arises from the side of the cricoid carti- 

 lage, and from the oblique line and upper and lower borders 

 of the ala of the thyroid cartilage ; from this origin the 

 bres are directed backward in a radiated manner to meet 



ose of the corresponding muscle of the opposite side. 

 hey unite and form a tendinous raphe along the posterior 

 median line of the pharynx. The lower fibres are continu- 

 ous with the muscular fibres of the oesophagus. The recur- 

 rent laryngeal nerve passes under its lower border. 



The CONSTRICTOR MEDIUS arises from the greater cornu 

 of the os hj'oides, and from the stylo-hyoid ligament ; its 

 fibres radiate from this origin, and blend along the middle 

 line with the muscle of the other side, ending at its upper 

 border in the aponeurosis of the pharynx. Tiie glosso- 

 pharyngeal nerve passes under the upper border of this 

 muscle, and the stylo-phaiyngeus muscle separates it from 

 the superior constrictor. 



The stylo-pharyngeus muscle, already described (p. 51), 

 is again seen in this connection ; arising from the base of the 

 styloid process, and descending between the superior and 

 middle constrictor, it is inserted partly into the pharynx, 

 and partly into the upper border of the thyroid cartilage, 



The stylo-hyoid ligament, already described (p. 51), is 

 again seen extending from the tip of the styloid process of 

 the temporal bone to the lesser cornu of the os hyoldes. 



The CONSTRICTOR SUPERIOR arises from the inner surface 

 of the internal pterygoid plate, from the pterygo-maxillary 

 ligament, the mucous membrane of the side of the mouth, 

 mid from the posterior part of the mylo-hyoid ridge of the 

 lower jaw ; from this extensive and irregular origin its 

 fibres pass backward, and are inserted into the pharyngeal 

 aponeurosis. The portion arising from the mucous mem- 

 brane of the mouth has been described as a separate mus- 

 cle, called the glosso-pharyngeus. 



The pterygo-maxillary ligament is the raphe of union 

 which exists between the superior constrictor and the bucci- 

 nator muscles, one extremity being attached to the hamular 

 process of the internal pterygoid plate, and the other to 

 the extremity of the molar ridge of the lower jaw. 



The pharyngeal aponeurosis connects the muscular part 

 of the pharynx with the base of the skull, being attached 

 superiorly to the basilar process of the occipital bone and 

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