THE LARYNX. 



531 



envelop their external face ; their inferior extremity is fixed into the crico-thyioid 

 membrane, and the angle of the thyroid cartilage ; the superior is attached to the 

 inferior border of the arytsenoid cartilage, towards the angle which separates this 

 from the posterior border. The articulation of sounds is principally due to the 

 vibration of these cords (Fig. 313, D). 



F. The epiglottis is attached by amphiarthrosis to the body of the thp'oid 

 cartilage, by means of elastic fasciculi mixed with fat, which pass from the base 

 of the first to the upper face of the second. It is not rare to find among these 

 fasciculi small synovial bui-sae. 



G. The epiglottis is united, laterally, to the inferior border of the arytsenoids, 

 through the medium of the two mucous folds already noticed, in the substance 

 of which are the cartilaginous prolongations annexed to the base of this fibro- 

 cartilage. These prolongations circumscribe, anteriorly, the ventricles of the 



Fig. 312. 



Fig. 313. 



SUPERIOR FACE. 



INFERIOR FACE. 



CARTILAGES OF THIC LARYNX, HELD IN THEIR NATURAL POSITION BY THE ARTICULAR 



LIGAMENTS. 



a Cricoid cartilage ; 6, b, arytaenoid cartilages ; c, body of the thyroid ; c', c', lateral plates of the- 

 thyroid; d, epiglottis; e, body of the hyoid bone; /, trachea. 1, Crico-arytaenoid articulation; 

 2, capsule of the crico-thyroid articulation; 3, crico-thyroid membrane; 4, thyro-hyoid mero- 

 brane ; 5, crico-trachealis ligament. 



larynx, and are sometimes designated the superior vocal cords — a name rarely given, 

 them, as they do not merit it. 



H. Finally, the first ring of the trachea is attached to the cricoid cartilage by 

 -a circular elastic membrane. 



All of these articulations have neither the same importance nor mobility. 

 The kind of movements they permit is easily understood, and they are sufficiently 

 indicated in the description of the muscles which execute them. 



It is sufficient here to state, that these movements may either produce the 

 shortening or elongation of the larynx, its dilatation or contraction in a transverse- 

 direction, or the occlusion of its anterior opening. 



2. Mmrles of the larynx. — The laryngeal apparatus is elevated or depressed 

 with the hyoid bone, which it follows in all its movements. It is also moved 



