Abstract: Objective To estimate the chronological age of Han teenagers in Sichuan by the epiphyses development characteristics of iliac crest and ischial tuberosity in X-ray digital images. Methods According to TW2 classification principle, combining with the age range of our subjects and epiphyses development regularity, the degree of epiphyses development of iliac crest and ischial tuberosity had been divided into 8 grades （0-7） and 7 grades （0-6）, respectively. Based on the degrees, the pelvic X-rays digital images of 691 samples of 16-20 aged teenagers were read and statistically analyzed by SPSS 19.0 software. The multiple linear regression equation was established by skeletal age （Y）, development degree of iliac crest epiphyses （X1） and ischial tuberosity epiphyses （X2）. Results There were no statistical differences between two sides of epiphyses development of iliac crest and ischial tuberosity （P>0.05）. There were no statistical difference between genders （P>0.05）. The re-substitution method of the samples showed that the accuracy of equation as Y=15.269+0.444 X1+0.236 X2 was high. The result of the re-substitution method showed a high accuracy of the equation. Conclusion The multiple linear regression equation could be used to identify the skeletal age for providing the scientific basis to identify the 18-year-old Han population in Sichuan.

Key words: forensic anthropology, age determination by skeleton, pelvis, tomography, X-ray computed, Sichuan, Han nationality