ANATOMY OF THE LARYNX 



483 



GROUP. 



MUSCLE. 



ATTACHMENTS. 



ACTION. 



II. and III. 

 Adductors 



and 

 Sphincters. 



D. Middle 

 layer. 



i. A r y t e 

 n o i d e u s 

 posticus. 



ii. Thyro- 

 ary tenoi- 

 dei ex - 

 terni. 



n three lay- 

 ers: 



Outer 



layer, Thy- 

 r o - a r y - 

 epiglot- 

 tici. 



iii. Crico- 

 arytenoi 

 del late 

 rales. 



c. Inner 

 most layer 

 Thyro-ar y 

 tenoidei in 

 terni. 



pair of muscles. Flat and narrow, 

 which arise on either side from the 

 processus muscularis of the arytenoid 

 cartilage, then passing upward and in- 

 ward cross one another in the middle 

 line to be inserted into the upper half 

 of the lateral border of the opposite 

 arytenoid cartilage and the posterior 

 border of the cartilage of Santorini. 

 The lower fibers run forward and 

 downward to be inserted into the 

 thyroid cartilage near the commissure. 

 The fibers attached to the cartilage of 

 Santorini are continued forward and 

 upward into the ary-epiglottic fold. 



single muscle. Half-quadrilateral, 

 attached to the borders of the ary- 

 tenoid cartilages, its fibers running 

 horizontally between the two. 



A pair of muscles. Each of which con- 

 sists of three chief portions. The 

 lower and principal fibers arise from 

 the lower half of the internal surface 

 of the thyroid cartilage, close to the 

 angle, and from the fibrous expansion 

 of the crico-thyroid ligament, and are 

 inserted into the lateral border of the 

 arytenoid cartilage. The inner fibers 

 to the lower half of this border, anc 

 the outer fibers into the upper half 

 some pass to the cartilage of Wrisberg 

 and the ary-epiglottic fold. 



A pair of muscles. They arise on eithe: 

 side from the middle third of the up 

 per border of the cricoid cartilage anc 

 are inserted into the whole anterio: 

 margin of the base of the arytenok 

 cartilage. Some of their fibers join 

 the thyroid -ary-epiglottici. 



A pair of muscles. They arise on eithe 

 side, internally from the angle of the 

 thyroid cartilage, internal to the las 

 described muscle, b. iii., and running 

 parallel to and in the substance of the 

 vocal cords are attached posteriorly to 

 the processus vocalis and to the oute 

 surface of the arytenoid cartilages. 



lelp to narrow or 

 close the rima 

 glottidis. 



Oraws together the 

 arytenoid carti- 

 lages and also de- 

 presses them. 

 When the mus- 

 cle is paralyzed, 

 the inter-carti- 

 laginous part of 

 the cords cannot 

 come together. 



Approximate the 

 vocal cords 

 by drawing the 

 processus muscu- 

 laris of the ary- 

 tenoid cartilages 

 forward and 

 downward and so 

 rotate the pro- 

 cessus vocalis in- 

 ward. 



Render the vocal 

 cords tense and 

 rotate the aryte- 

 noid cartilages 

 and approximate 

 the processus vo- 

 calis. 



