THE PHARYNX 



349 



attached to the base of the skull, the great cornu of the hyoid bone, and the 

 thyroid cartilage of the larynx. They are as follows: 



1. The stylo-pharyngeus arises from the inner surface of the dorsal third of the 

 great cornu of the hyoid bone, passes downward and inward, and enters the wall of 

 the pharynx by passing between the pterygo-pharyngcnis and palato-pharyngeus. 

 Its fibers radiate, many passing forward, others inward beneath the hyo-pharyngeus. 

 It raises and dilates the pharynx to receive the bolus in swallowing. 



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Septum 

 nasi 





jMcerebellum 



31 30^ 



/^ons Medulla *' 





Fig. 254 — Posterior Part of a Sagittal Section of Hf.ad of Horse, Cut about 1 cm. to the Left of the 



Median Plank. 

 /, Posterior nares; 2, pharyngeal orifice of Eustachian tube; 3, aditus laryngis; 4, entrance to cesophagus; 

 5, posterior pillar of soft palate; 5', junction of -5 with its fellow over entrance to oesophagus; 6, epiglottis; ~, body 

 of thyroid cartilage; (?, arytenoid cartilage; 9, 5, cricoid cartilage; 10, true vocal cord; 11, false vocal cord; 12, 

 lateral ventricle of larynx; i5, crico-arytenoideus post. s. dorsalis; 74, oesophagus; /a, external carotid artery; 16, 

 hypoglossal nerve; 17, glosso-pharyngeal nerve; 18, great cornu of hyoid bone; 19, Eustachian tube; 20, body of 

 hyoid bone; 21, hyoideus transversus; 22, ridges of hard palate; 22', soft palate; 23, septum between frontal 

 sinuses; 24, olfactory mucous membrane; 25, sphenoidal sinus; 26, basilar part of occipital bone; 26' . supra- 

 occipital; ;27', body of si)henoid hone; .?i', pituitary body; ^S, chiasma opticum; ^0, corpora quadrigemiiia; 31, 

 thalamus; 3.2, arachnoid; 33, odontoid ligament; 34, posterior auricular muscles. 



2. The palato-pharyngeus arises by means of the aponeurosis of the soft 

 palate from the palate and pt(>rygoid bones. Its fibers pass backward on the lateral 

 wall of the pharynx, and are inserted in part into the upper edge of the thyroid 

 cartilage, in part turn inward to end at the median fibrous raphe. Its action is to 

 shorten the pharynx, and to draw the larynx and oesophagus toward the root of the 

 tongue in swallowing. 



3. The pterygo-pharyngeus is flat and triangular. It lies on the anterior part 

 of the lateral wall of the pharynx. It arises from the pterygoid bone above the 



