CHAP, vii.] SPECIAL MUSCULAR MECHANISMS. 



319 



externus) (Figs. 188, m.th.ar.e. 184 B). The direction of the muscle 

 as a whole is horizontally backwards, though inclined outwards 

 and upwards, but the constituent individual bundles run in various 



m.th.ar.j 



rn.th.ar.e~/. 

 mih.ar.ep 



pm Oe rh.ar.t 



FIG. 188. DIAGRAM TO ILLUSTRATE THE THYRO-ARYTENOID MUSCLES. 



The figure represents a transverse section of the Larynx through the bases of the 

 arytenoid cartilages. 



Ary. Arytenoid cartilage, p.m. processus muscularis. p.v. processus vocalis. 

 Th. Thyroid cartilage, c.v. vocal cords. Oe. is placed in the oesophagus. 



m. th. ar. i. internal thyro-arytenoid muscle, m. th. ar. e. external thyro-arytenoid 

 muscle, m.th.ar.ep. part of the thyro-ary-epiglottic muscle cut more or less 

 transversely. 



-I.cr. ar., 



FIG. 189. THE INTERNAL THYRO-ARYTENOID MUSCLE. 



The left halves of the thyroid and cricoid have been removed so as to shew the 

 right arytenoid in position. 



Th. Thyroid. Cri. Cricoid. Ary. Arytenoid. S. Cartilage of Santorini. 1. cr. ar. 

 the crico-arytenoid ligament, m. th. ar. i. the internal thyro-arytenoid muscle, 

 with c.v. the vocal cord. 



ways and some even pass vertically into the ventricular bands. To 

 the inner or median side of this external muscle, between it and 

 the corresponding vocal cord, lies the inner muscle which running 



