1 83 



NORMAL HISTOLOGY. 



columnar, except over the laryngeal surface of the epiglottis, the anterior 

 aspect of the arytenoid cartilages and the true vocal folds, where the epi- 

 thelium is of the stratified squamous variety. In this respect, however, the 

 mucosa of the upper half of the larynx presents many individual variations, 

 since patches of squamous epithelium are often observed within the more 

 general lining of columnar cells. Small scattered taste-buds are often seen 

 in the epithelium covering the epiglottis. The tunica propria consists of 

 closely packed bundles of fibrous tissue, with an abundance of elastic fibres. 

 It contains many lymphoid cells which in certain locations, as over the epi- 

 glottis and especially in the ventricle of the larynx (the lateral diverticulum 



Glands 



Epiglottis 



False vocal cord ^ftf 



Lymphoid tissue 

 True vocal cord 



Thyro-arytenoid 

 muscle 



Thyroid cartilage 



Lateral crico- 

 arytenoid muscle 



Cricoid cartilage 



FIG. 234. Frontal section of larynx passing through epiglottis, vocal folds and ventricle ; the plane of 

 section is at right-angles to that of preceding figure. X 2%. 



between the false and true vocal folds), are aggregated into distinct although 

 small lymph-nodules (Fig. 234). 



The submucous layer, composed of loosely disposed bundles of fibro- 

 elastic tissue, varies in amount in different parts of the larynx, with corre- 

 sponding modifications in the intimacy of attachment of the mucous membrane 

 to the surrounding structures. Thus, it is meagre over the free part and 

 laryngeal surface of the epiglottis, the arytenoid and lower part of the cricoid 

 cartilages, in which positions the mucosa is closely attached. Over the true 

 vocal folds the submucosa is practically wanting. On the other hand, 

 in the aryepiglottic folds (which bound laterally the superior laryngeal orifice) 

 and in the ventricle it is abundant, with consequent mobility of the mucosa. 

 The submucous layer contains many groups of small mixed mucous tubo- 

 alveolar glands. They occupy pits in the cartilage of the epiglottis, and 



