Abstract: Objective According to the features of epiphyseal development of knee and ankle joints in male and female teenagers,the trend of epiphyseal development was analyzed and the possibility of its application in age estimation was discussed. Methods Firstly,radiographs of adem position were taken from both sides of knee and ankle joints from 1 709 individuals from Eastern China,Central China,and Southern China (Age:11-21 years old). Secondly,5 osteal loci were selected as bone age markers from the two joints. Thirdly,characteristics of epiphyseal development were observed systematically and comprehensively. Fourthly,the proportions of "epiphyseal fusion" in different age groups were calculated,and confirmed the numbers of people which were included by epiphyseal fusion of knee and ankle joints. Finally,age range of each epiphyseal fusion was calculated by mathematical statistical analysis. Results Compared with the data of 1960s',the age of 5 epiphyseal fusions was earlier about 2-3 years. However,the results were basically the same as the recent studies. Conclusion The data on the time of epiphyseal fusion were updated. It is important to determine the accuracy in age estimation in male and female teenagers.

Key words: forensic anthropology, adolescent, epiphyses, knee joint, ankle joint