Subepithelial mucous glands in the adult human larynx. Studies on number, distribution and density

The entire intra- and extralaryngeal mucosa from 10 adult persons having macroscopically normal larynges was examined by the whole-mount method and selective staining of the mucous elements by PAS-alcian blue in order to assess the number, distribution, and density of the subepithelial glands. After microdissection of the mucosa the glandular orifices were quantitated under the stereomicroscope. Glands were demonstrated in the various regions of all larynges. The total intralaryngeal number, when excluding the saccule, ranged between 603 and 1579 (median 890) glands. In 6 larynges, glands could be quantitated in the saccule, where their number ranged between 32 and 324 (median 89). In the extralaryngeal region the count for the total series ranged between 1 and 53 (median 9) glands. The median intralaryngeal density, excluding the saccule, was 0.27 gland/mm2, ranging between 0.23 and 0.47. The density was significantly greater in the glottic than in the sub- and supraglottic regions. The highest concentration of glands was observed in the saccule in which the median density was 0.82 gland/mm2. A correlation between gland density and age or sex was not demonstrable. On the basis of the results, the subepithelial glands must be considered a normal component of the mucociliary system in the laryngeal mucosa.