Growth, Development and Aging of the Vocal Fold

Abstract

We investigated 88 human larynges obtained from autopsy cases. Their age ranged from zero (newborn) to the seventh decade. The results are as follows:
(1) The length of the vocal fold was 2.5-3mm in newborns. It was defined as the distance between the anterior commissure and the posterior end of the ventricle. It increased with the age up to 20 years. In adults, the vocal fold length was 17-21mm in males and 11-15mm in females.
(2) The length of the membraneous portion was 1.3-2mm in newborns. It also increased with age up to 20 years. In adults, the length of the membraneous portion was 14.5-18mm in males and 8.5 to 12mm in females.
(3) The length of the cartilaginous portion was 1.1-1.8mm in newborns. It increased with age. Its increase, however, was much less than that of the membraneous portion. Therefore, the ratio of the membraneous portion to that of the cartilaginous portion was much greater in adults than in young children.
(4) The thickness of the mucosa was 0.75-0.95mm in newborns. It slightly increased with the age.
(5) There was no vocal ligament in newborns. There were only immature maculae flavae. An immature ligamentous structure appeared at the ages of 1 to 4. Differentiation of the two layers in the ligament, i. e. the layer of elastic fibers and that of collagen fibers, occurred at the age of 6 to 12. The vocal ligament appeared to become mature before 20 years of age.
(6) With aging, significant histological changes occurred in the lamina propria of the vocal fold mucosa. The superficial layer thickened because of edema. The intermediate layer thinned because of the atrophy of the elastic fibers. The deep layer thickened due to a fibrotic increase of the collagenous fibers.