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AN AMERICAN TEXT-BOOK OF PHYSIOLOGY. 



which fibres, though having a general longitudinal course, are interwoven, and 

 send off shoots laterally into the subjacent tissue. The compact ligament, 

 known commonly as the " vocal cord," forms only the free edge of a reflexion 

 from the side wall of the larynx. This reflexion is wedge-shaped in a vertical, 

 transverse section and contains much elastic tissue and the internal and part 

 of the external thyro-arytenoid muscle (Fig. 295). This whole structure 



properly forms the vocal cord, and by 

 contraction of its contained muscle its 

 thickness and vibrating qualities may 

 be greatly modified. 



Like the trachea, the larynx, with the 

 exception of the vocal cords, is lined 



7- 



17 



-.18 



FIG. 296. Cartilages of the larynx, separated 

 (Stoerk) : 1, epiglottis ; 2, petiolus ; 3, median 

 notch of thyroid ; 4, superior cornu of thyroid ; 

 5, attachment of stylo-pharyngeus muscle; 6, 

 origin of thyro-epiglottic ligament ; 7, origin of 

 the thyro-arytenoid muscle; 8, origin of true 

 vocal cord ; 9, inferior cornu of thyroid ; 10, car- 

 tilage of Wrisberg ; 11, cartilage of Santorini ; 12, 

 12', arytenoid cartilages, showing attachments of 

 the transverse arytenoid muscle ; 13, 13', pro- 

 cessus muscularis, showing attachments of the 

 posterior and lateral crico-arytenoid muscles; 

 14, base of the arytenoid cartilage ; 15, vocal pro- 

 cesses of the arytenoids ; 16, articular surface for 

 the base of the arytenoid cartilage ; 17, posterior 

 view of cricoid cartilage, with outline of attach- 

 ment of the posterior crico-arytenoid muscle; 

 18, articular surface for inferior cornu of thyroid 

 cartilage. 



FIG. 297. Cartilages and ligaments of the 

 larynx, posterior view (after Stoerk) : 1, epiglot- 

 tis; 2, cushion of the epiglottis; 3, cartilage of 

 Wrisberg ; 4, ary-epiglottic ligament ; 5, 8, mucous 

 membrane ; 6, cartilage of Santorini ; 7, arytenoid 

 cartilage ; 9, its processus muscularis ; 10, crico- 

 arytenoid ligament; 11, cricoid cartilage; 12, in- 

 ferior cornu of thyroid cartilage ; 13, posterior 

 superior cerato-cricoid ligament; 13', posterior 

 inferior cerato-cricoid ligament; 14, cartilages 

 of the trachea; 15, membranous portion of 

 trachea. 



by columnar, ciliated epithelium, the direction of whose movement is upward 

 toward the pharynx. The vocal cords are covered by thin, flat, stratified epi- 

 thelium. The inner surface of the epiglottis, the walls of the ventricles, and 

 the ventricular bands contain much adenoid tissue, the spaces of which are apt 

 to become distended with fluid, giving rise to O3dema of those parts. The 

 whole mucous membrane of the larynx, except over the vocal cords, is richly 

 supplied with glands both mucous and serous in character. 



