Several developmental changes in the skull of infants and children are well documented and have been used in the estimation of age at death of infants and children. This paper will present a feature of the infant and child temporal bone, the development of the tympanic plate (floor) of the external auditory meatus, which has recently proven useful in age estimation. Through the use of the Likelihood Ratio Test (Sprott, '73), a six-stage developmental sequence for the tympanic plate has been evaluated. Analysis of tthe tympanic plate developmental sequence has produced the following age categories: fetal, newborn, six months, one to two and one-half years. A general discussion of the basis and potential applications of the Likelihood Ratio Test for analysis of stages and other ordinal data is offered.