THE PHARYNGEAL REGION. 



419 



two muscles, acting along the middle line of the tongue, draw it downward, so as to 

 make it concave from side to side, forming a channel along which fluids may pass 

 toward the pharynx, as in sucking. The Hyo-glo9*i muscles depress the tongue 

 and draw down its sides, so s to render it convex from side to side. The Stylo- 

 </ muscles draw the tongue upward and backward. The Palato-glossi muscles 

 draw the base of the tongue upward. With regard to the intrinsic muscles, both 

 the Superior and Inferior linguales tend to shorten the tongue, but the former, in 

 addition, turn the tip and sides upward so as to render the dorsum concave, while 

 the latter pull the tip downward and cause the dorsum to become convex. The 

 Transverse lingualis narrows and elongates the tongue, and the Vertical lingualis 

 flattens and broadens it. The complex arrangement of the muscular fibres of 

 the tongue, and the various directions in which they run, give to this organ the 

 power of assuming the various forms necessary for the enunciation of the different 

 consonantal sounds ; and Dr. Macalister states that " there is reason to believe 

 that the musculature of the tongue varies in different races owing to the hereditary 

 practice and habitual use of certain motions required for enunciating the several 

 vernacular languages." 



5. Pharyngeal Region. 



Inferior constrictor. 



Middle constrictor. 



Palato-pharyngeus. 1 

 Salpingo-pharyngeus. J 



Superior constrictor. 

 Stylo-pharyngeus. 



(See next section.) 



Dissection Fisr. 2^2 . In order to examine the muscles of the pharynx, cut through the 

 trachea and oesophagus just above the sternum, and draw them upward by dividing the loose 

 areolar tissue connecting the pharynx with the 

 front of the vertebral column. The parts 

 being drawn well forward, apply the edge of 

 the saw immediately behind the styloid pro- 

 and saw the base of the skull through 

 from below upward. The pharynx and mouth 

 should then be stuffed with tow. in order to 

 distend its cavity and render the muscles tense 

 and easier of dissection. 



The Inferior constrictor, the most 

 superficial and thickest of the three 

 constrictors, arises from the sides of the 

 cricoid and thyroid cartilages. To the 

 cricoid cartilage it is attached in the 

 interval between the Crico-thyroid mus- 

 cle in front and the articular facet for 

 the thyroid cartilage behind. To the 

 thyroid cartilage it is attached to the 

 oblique line on the side of tLe great ala. 

 the cartilaginous surface behind it. near- 

 ly as far as its posterior border, and to 

 the inferior cornu. From these attach- 

 ments the fibres spread backward and 

 inward, to be inserted into the fibrous 

 raphe in the posterior median line of 

 the pharynx. The inferior fibres are 

 horizontal, and continuous with the 

 fibres of the oesophagus : the rest as- 

 cend, increasing in obliquity, and over- 

 lap the Middle constrictor. The supe- 

 rior laryngeal nerve and artery pass 

 near the upper border, and the inferior, or recurrent laryngeal, beneath the lower 

 border of this muscle, previous to their entering the larynx. 



Relations. It is covered by a dense cellular membrane which surrounds the 



FIG. 382. Muscles of the pharynx. External view. 



