Age Estimation by Tympanic Bone Development in Foetal and Infant Skeletons

Abstract

This article analyses age-related changes in the development of the temporal bone in a sample of foetal and infant skeletons to contribute to the estimation of age by means of this skeletal element in bioarchaeological and forensic contexts. The sample was selected from a contemporary documented skeletal collection and is constituted by the temporal bones of individuals of both sexes (n=37) with ages from 23weeks of gestation up to 11 postnatal months. Different states of fusion of the tympanic ring and development of the tympanic plate were scored separately, and intra-observer consistency was evaluated. Both documented chronological age and skeletal estimated age were examined in relation to successive stages of fusion and development in the pre- and postnatal periods. It was found that the state of fusion of the tympanic ring is especially useful in the discrimination of foetal and postnatal individuals, whereas the development of the tympanic plate is helpful in the differentiation of individuals from and below 3 postnatal months. Even though a certain degree of overlap between successive stages was observed, the fusion of the tympanic ring and the development of the tympanic plate constitute good indicators of age in foetal and infant skeletons.