410 HEAD AND NECK 



slightly arched, with the concavities looking downwards. 

 Within each fold are contained (i) a ligamentum ventriculare ; 

 (2) numerous glands which are chiefly aggregated in its middle 

 part ; and (3) a few muscle fibres. The interval between the 

 ventricular folds is termed the rima vestibuli it is consider- 

 ably wider than that between the vocal folds. It follows, 

 therefore, that the four folds are distinctively visible when 

 the cavity of the larynx is examined from above, but when 

 examined from below, the vocal folds alone can be seen. 



Plica Vocales (O.T. True vocal cords]. The vocal folds are 

 placed below the ventricular folds, and extend from the angle 

 between the laminae of the thyreoid cartilage, anteriorly, to the 



Base of tongue 



Glosso- 



epiglottic 



fold 



Epiglottis 

 Tubercle 



Plica vocalis 



Cuneiform cartilage 



Corniculate cartilage 



FIG. 158. The Larynx as seen in the living person by means of the 

 Laryngoscope. 



vocal processes of the arytaenoid cartilages posteriorly. Each 

 vocal fold is sharp and prominent, and its mucous membrane is 

 thin and is firmly bound down to the subjacent vocal ligament. 

 In colour it is pale, almost pearly white, whilst posteriorly 

 the point of the vocal process of the arytaenoid cartilage, 

 which stands out in relief, presents a yellowish tinge. In 

 frontal section each vocal fold is somewhat prismatic in form, 

 and the free border looks upwards and medially (Fig. 157). 



The vocal folds are the agents by means of which the voice 

 is produced. The ventricular folds are of little importance 

 in this respect ; indeed, they can in great part be destroyed 

 without any appreciable difference in the voice resulting. 



The rima glottidis is the elongated fissure by means of 

 which the middle compartment of the larynx communicates 

 with the lower subdivision. It is placed somewhat below 



