360 



RESPIRATION. 



The glottis and the true vocal cords demand a somewhat more 

 detailed description than given above, owing to their importance 

 in connection with respiration and phonation. 



Glottis (Figs. 194-196, 199-201). This opening differs in 

 shape under different conditions. Its length from the angle of the 

 true vocal cords in front to the vocal processes of the arytenoid 

 cartilages behind is about 2.5 cm., and its breadth when dilated 

 varies from 0.8 cm. to 1.2 cm. During ordinary inspiration its 

 breadth increases, becoming triangular, and in very deep or forced 



FIG. 199. The voicing (female) larynx: A, small or highest register; B, upper 

 thin or middle register; (7, lower thin or middle register; T, T, tongue; F, F, false 

 vocal cords ; 8, S, cartilages of Santorini ; W, W, cartilages of Wrisberg ; V, V, vocal 

 cords (after Browne and Behnke). 



inspiration lozenge-shaped, while during phonation the vocal cords 

 are more approximated than at the end of respiration. 



FIG. 200. The larynx in gentle 

 breathing: L, epiglottis ;F, vocal cords; 

 8, cartilages of Santorini, which sur- 

 mount the arytenoid cartilages ; P, P, 

 ventricular bands (Lennox- Browne). 



FIG. 201. The larynx in deep breath- 

 ing: WP, tracheal rings; B, openings 

 of bronchi ; P, P, ventricular bands 

 (Lennox-Browne) . 



The changes which take place during voice-production are more 

 fully considered in connection with that function of the larynx 

 (p. 389). 



True Vocal Cords. These are called also vocal bands and vocal 

 ligaments. They consist of strong fibrous bands covered with 

 mucous membrane, and parallel with them and attached to them 

 are the inner portions of the thyro-arytenoid muscles. 



The mucous membrane lines the entire larynx, and forms the 

 folds already described. Below the false vocal cords it is covered 

 with columnar ciliated epithelium. Above these cords cilia are only 

 found in front up to the middle of the epiglottis. Elsewhere, in- 

 cluding the true cords, the epithelium is stratified. 



Vessels and Nerves. The arteries which supply the larynx 

 are derived from the superior and inferior thyroid. The nerves are 



