Intra-epithelial mucous glands in the adult human laryngeal mucosa

By means of elective staining with PAS-alcian blue and a whole-mount technique, the entire mucosa from 10 macroscopically normal human adult larynges was investigated with a view to describing the morphology, number, and distribution of the intra-epithelial glands. The glands varied in shape from round to oblong and in size between 30 and 200 micron. The typical round intra-epithelial gland was found to consist of 15-30 mucus-secreting cells, radially arranged around a narrow lumen debouching in a narrow stoma surrounded by cilia. The glands were of irregular distribution in all regions of the larynx. In each larynx there were between 174 and 652 (median 309) intra-epithelial glands. The most striking finding was a pronounced fall in their number from the supraglottis to the subglottis. Two larynges contained intra-epithelial cyst-like structures measuring from 15 to 40 micron. In the supraglottis there was a significantly negative correlation between the occurrence of intra-epithelial and subepithelial glands. On the other hand, it was not possible to demonstrate a definite relationship between the active intra-epithelial glands and the cystic intra-epithelial structures.