THE LARYNX 



1175 



the most superficial, form two fasciculi, which pass from the base of one cartilage 

 to the apex of the opposite one, and which, therefore, cross each other like the 

 limbs of the letter X. The transverse fibres (m. arytaenoideus transversus), the 

 deepest and most numerous, pass transversely across between the two cartilages. 

 A few of the oblique fibres are continued around the outer margin of the cartilage, 

 and blend with the Thyroarytenoid in the arytenoepiglottic fold, and are called 

 the Aryepiglotticus muscle. 



The Thyroarytenoid (m. thyroarytenoideus) (Figs. 888 and 889), a paired muscle, 

 is broad and flat. It lies parallel with the outer side of the true vocal cord. It 

 arises in front from the lower half of the receding angle of the thyroid cartilage, 

 and from the cricothyroid membrane. Its fibres pass backward and outward, to 

 be insrrird into the base and antero-external surface of the arytenoid cartilage. 

 This muscle consists of two fasciculi. 1 The inner portion (m. vocalis) is a tri- 

 angular band which is inserted into the 

 vocal process of the arytenoid cartilage, 

 and into the adjacent portion of its antero- 

 external surface; it lies parallel with the 

 true vocal cord, to which it is adherent. 

 This fasciculus on its deeper surface 



Cornicula 



Articular facet 

 inferior comn 

 thi/roid cartilage 



of 



FIG. 



is. Muscles of larynx. Side view, 

 of thyroid cartilage removed. 



Right ala 



FIG. 889. Interior of the larynx, seen from above. 

 (Enlarged.) 



gives off some fibres which are attached to the true vocal cord- These are called 

 the Aryvocalis (Ludwig). The outer portion (m. thyreoarytenoideus), the thinner, 

 is inserted into the antero-external surface and outer border of the arytenoid 

 cartilage above the preceding fibres; it lies on the outer side of the laryngeal saccule, 

 immediately beneath the mucous membrane. 



A considerable number of the fibres of the Thyroarytenoideus are prolonged 

 into the arytenoepiglottic fold, where some of them become lost, while others 

 are continued forward to the margin of the epiglottis. They have received a 

 distinctive name, Thyroepiglotticus (m. thyreoepiglotticus), and are sometimes 

 described as a separate muscle. 



1 Henle describes these two portions as separate muscles, under the names of the External and Internal 

 thyroarytenoids. 



