Ultrastructure of the Mucous Membrane of the Human Newborn Vocal Folds.

This study was carried out to determine the ultrastructure of the mucous membrane of vocal folds of human newborns. Excised larynges of newborns were observed with a transmission electron microscope. The results obtained are summarized as follows: 1) The epithelium of the edge of the vocal folds consisted of stratified squamous epithelium. It was thin but numerous desmosomes showed firm attachment between cells. 2) The basement membrane zone had the same structure as that of adults. 3) The lamina propria of the vocal fold mucosa was loose in structure and there was no vocal ligament. 4) Fibroblasts were sparse and in the resting phase. 5) Collagenous and elastic fibers were sparse in the lamina propria. Structures of the the collagenous fibers wee mature but those of elastic fibers, were immature morphologically. 6) Ground substance was abundant in the lamina propria. 7) The newborn vocal fold mucosa lacked not only a vocal ligament but also adequate viscoelasticity for vibration.