THE LARYNX 



337 



that its vocal process passes laterally and the vocal folds are 

 abducted (Fig. 120). 



(d) The crico-arytsenoideus lateralis arises from the antero- 

 lateral surface of the cricoid and passes upwards, backwards 

 and laterally to reach the muscular process of the arytsenoid. 

 Since its line of pull is anterior to the centre of the crico- 



i. ii. 



FIG. 1 20. Transverse Section through the Larynx at the level of 

 the vocal folds (true vocal cords). (TURNER'S Anatomy.) 



I. The vocal folds are abducted and the rima glottidis is widely open. 

 II. The vocal folds are adducted. Notice the alteration in the position of the 

 arytaenoid cartilages. 



A. Arytaenoid cartilage. 

 C. Cricoid cartilage. 

 T. Thyreoid cartilage. 

 a. Vocal process of arytaenoid cartilage. 

 at. Arytaenoideus transversus. 

 e. Muscular process of arytaenoid 

 cartilage. 



lea. Crico-arytaenoideus lateralis. 

 Pea. Crico-arytaenoideus posterior. 



r. Inter-cartilaginous part of rima glot- 

 tidis (glottis respiratoria). 

 ta. Musculus vocalis. 

 v. Inter-membranous part of rima 

 glottidis (glottis vocalis). 



arytsenoid joint, the vocal process is rotated in a medial 

 direction (Fig. 120) when the muscle contracts. It is therefore 

 an adductor of the vocal folds. 



The arytsenoideus muscle connects the two arytaenoid 

 cartilages, and its contraction draws them close to one 

 another, posteriorly. 



With the single exception of the crico-thyreoid, which is 

 supplied by the external laryngeal nerve (p. 97), all the 



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