THE LAKYXX 233 



the epiglottis, as far as the false vocal cords is lined by stratified 

 epithelium which is continuous with that of the pharynx. 



The epithelium of the vocal cords and that covering the ante- 

 rior surface of the arytenoids is also of the stratified squamous 

 variety. The remaining portions of the larynx, including the base 

 of the epiglottis on its laryngeal surface, the ventricle, and the 

 entire portion below the level of the true vocal cords, are lined by 

 columnar ciliated epithelium of the pseudo-strati fied type. The 

 ciliary motion is directed toward the pharynx. The epithelium 

 rests upon a basement membrane which is less highly developed 

 than in other portions of the respiratory tract. 



The tunica propria consists of connective tissue in which are 

 many small tubulo-acinar mucous glands. These are most abun- 

 dant in the region of the ventricle and the false vocal cords. In 

 this region also there is much diffuse lymphoid tissue, and the 

 lateral and dorsal wall contains several lymphatic nodules which 

 are so constant in their appearance as to have led Frankel* to 

 describe them as forming a "laryngeal tonsil." Occasionally, 

 however, lymphatic nodules are not present in the mucous mem- 

 brane of the human larynx. The deeper portion of the tunica 

 propria in certain parts, e. g., in the false vocal cords, contains a 

 few muscle fibres in addition to those of the named muscles of the 

 larynx. The false vocal cords and the aryteno-epi glottic folds 

 contain loose fibrous tissue and frequently much fat. 



The true vocal cords are formed by dense bands of elastic and a 

 few white fibres which are covered by a mucosa clothed with strat- 

 ified epithelium. Their free margin is sharply defined ; at their 

 attached margin, however, they blend indistinctly with the tunica 

 propria. The free margin of the vocal cords has no connective 

 tissue papillae on the surface of the tunica propria, but toward the 

 trachea superficial papillae of connective tissue project into the 

 deeper surface of the stratified epithelium. 



The mucous membrane of the larynx is freely supplied with 

 blood vessels and lymphatics. The latter terminate in the deep 

 cervical lymphatic nodes. The nerve fibres form an abundant 

 plexus in the laryn'geal mucosa, from which motor fibres are dis- 

 tributed to the muscles and sensory fibres to the epithelium. The 

 latter end in fine fibrils between the cells of the lining epithelium. 

 In the stratified epithelium, especially that of the epiglottis, small 

 taste buds are also found ; none, however, occur on the vocal cords. 



* Arch. f. Laryngol. u. Rhinol., 1893. 



