THE VOCAL CORDS. 



695 



Vocal cords: 



construc- 

 tion. 



thyroid (fig. 249, 6 , p. 702), conies into view ; and it will be seen to and crico- 

 be continued upwards into, and give rise to the prominence of the membrane, 

 inferior or true vocal cord. Lastly, dissect off the mucous membrane 

 from the vocal cords on the right side, and in doing this the wall of 

 the ventricle and saccule, 

 which are formed mainly 

 by this membrane, will dis- 

 appear. 



The VOCAL CORDS (fig. 247) 

 are two bands on each side, 

 which extend from the angle 

 of the thyroid to the aryte- 

 noid cartilage, one forming 

 the upper, the other the 

 lower margin of the ventricle 

 of the larynx. Each consists 

 of a fold of the mucous 

 membrane supported by a 

 ligamentous structure the 

 superior and inferior thyro- 

 arytenoid ligaments respec- 

 tively. 



The superior or false -vocal 

 cord (c) is arched with its 

 concavity downwards, and is 

 much softer and looser than 

 the lower. Its free border is 

 thick and rounded. The 

 contained superior thyro-aryte- 

 noid ligament consists mostly 

 of white fibrous tissue, and 

 is fixed in front to the angle 

 of the thyroid cartilage near 

 the attachment of the epi- 

 glottis, behind to the middle 

 portion of the anterior sur- 

 face of the arytenoid carti- 

 lage. It is continuous above 

 with scattered fibrous bun- 

 dles in the aryteno-epiglot- 

 tidean fold. 



The inferior or true vocal cord (B) is attached in front to the angle 

 of the thyroid cartilage about half way down below the notch, and 

 behind to the vocal process of the arytenoid cartilage. Between 

 these points, its free margin, by the vibration of which the voice is 

 produced, is straight, sharp and smooth. The cord projects up wards 

 and inwards into the cavity of the larynx, and forms the boundary 

 of the vocal portion of the glottis. It is about ^ths of an inch long 

 in the male, and ^ths of an inch less in the female. The mucous 



Superior 

 cord, 



and thyro- 



arytenoid 



ligament. 



FIG. 247. VOCAL APPARATUS, OK A 

 VERTICAL SECTION OF THE LARYNX, 



A. Ventricle of the larynx. 



B. True vocal cord, 

 c. False vocal cord. 



D. Sac'culus laryngis. 



E. Arytenoid cartilage. 



F. Cricoid cartilage. 



G. Thyroid cartilage. 

 H. Epiglottis. 



K. Crico-thyroid membrane. 

 L. Thyro-hyoid membrane. 



Inferior 

 cord, 



