V. a new method for the assessment of skeletal maturity- the mat- method (mean appearance time of bone stages).

By means of probit analysis of the age at the appearance of the various bone stages according to Tanner-Whitehouse and using a logarithmic time concept (logarithmic conceptional age), a new approach to the evaluation of skeletal maturity has been elaborated. The maturity score of each bone stage corresponds to th4 mean maturity level of the observation of being within each stage. The individual maturity level is calculated by averaging the maturity scores of the stages of the various bones and is then evaluated is standard deviation scores by comparing with teh Gaussian fitted distribution of averages maturity scores of the age of the child examined. Special conditions apply for the scoring of a first and a last bone stage in a sequence, which will introduce less bias in the estimation of individual skeletal maturity with the MAT-method than with the TW-method. Ossification during early infancy can be evaluated and sequence polymorphism be detected by using the bone stage chart of the MAT-method.