544 



HANDBOOK OF PHYSIOLOGY. 



Movements of the Vocal Cords. 



In Respiration. The position of the vocal cords in ordinary tran- 

 quil breathing is so adapted by the muscles, that the opening of the 

 glottis is wide and triangular (fig. 347, B) becoming a little wider at 



Fig. 347. Three laryngoscopic views of the superior aperture of the larynx and surrounding 

 parts. A, the glottis during the emission of a high note in singing; B, in easy and quiet inha- 

 lation of air; C, in the state of the widest possible dilatation, as in inhaling a very deep breath. 

 The diagrams A', B', and C', show in horizontal sections of the glottis the position of the vocal 

 ligaments and arytenoid cartilages in the three several states represented in the other figures. 

 In all the figures, so far as marked, the letters indicate the parts as follows, viz. : /, the base of 

 the tongue; e, the upper free part of the epiglottis; e', the tubercle or cushion of the epiglottis: 

 ph, part of the anterior wall of the pharynx behind the larynx ; in the margin of the aryteno- 

 epiglottidean fold iv, the swelling of the membrane caused by the cartilages of Wrisberg ; s, that 

 of the cartilages of Santorini ; a, the tip or summit of the arytenoid cartilages; c i% the true 

 vocal cords or lips of the rima glottidis; cvs, the superior or false vocal cords; between them 

 the ventricle of the larynx; in C, tr is placed on the anterior wall of the receding trachea, 

 and 6 indicates the commencement of the two bronchi beyond the bifurcation which may be 

 brought into view in this state of extreme dilatation. (Quain after Czermak.) 



each inspiration, and a little narrower at each expiration. On making 

 a rapid and deep inspiration the opening of the glottis is widely dilated 

 (fig. 347, c), and somewhat lozenge-shaped. 



In Vocalization. At the moment of the emission of a note, it is nar- 

 rowed, the margins of the arytenoid cartilages being brought into contact 

 and the edges of the vocal cords approximated and made parallel, at 

 the same time that their tension is much increased. The higher the note 

 produced, the tenser do the cords become (fig. 347, A); and the range of 



