A three-dimensional reconstructive study of the layer structure of the human vocal cord.

The purpose of this investigation was to clarify the detailed histological structure of the human larynx and to clarify the cause of adaptation in high-frequency vibrations using three-dimensional histological reconstructions of human true vocal cords. In a first series of studies, 54 intact adult larynges were obtained from 398 human cavaders with known histories. Four of these laryngeal specimens were fixed in 10% formalin. Three of these were decalcified and embedded in paraffin and the other in Technovit-7100. The layer structure of each larynx was investigated with a three-dimensional reconstruction method using a personal computer. Results demonstrated that the elastic fiber layer in the superior surface of the vocal cord was wider than that in the inferior surface. The collagen fiber layer extends from the anterior commissure in a posterior direction. The elastic fiber layer connected both the anterior and the posterior macula flava, while the collagen fiber layer connected the thyroid cartilage and the anterior macula flava.