Pliability of the Vocal Fold Mucosa in Relation to the Occurrence of the Mucosal Upheaval

Abstract

Vocal fold vibration has been considered to be a transmission of mucosal waves which move upward from the mucosal upheaval. The mechanism of the occurrence of the mucosal upheaval has not been known yet. The purpose of this study was to relate the pliability of the mucosa to the occurrence of the mucosal upheaval. In addition, a histological basis for the occurrence of the mucosal upheaval was investigated. Five mongrel dogs were used in the experiment. After administration of an intramuscular Ketaral injection, the larynx was excised and divided vertically into two segments (hemilarynges). Pliability of the vocal fold mucosa was measured at 5-7 points ranging from the free edge to 8 mm below the edge at the middle, anterior forth and posterior forth of the membranous portion. Following the pliability measurements, each hemilarynx was fixed in formalin, sectioned in the frontal plane and stained for histologic examination. Results were summarized as follows :
1) The free edge showed the greatest pliability. The pliability of the mucosa became smaller as the edge became further. The mucosa at 3 mm below the free edge showed the least pliability.
2) The mucosa at the middle of the membranous portion had a greater pliability than that at the anterior and the posterior forth.
3) The lamina propria of the mucosa was thinnest at 3-4 mm below the free edge. At this thinnest point, the muscle layer was closest to the epithelial layer.