Abstract: Objective To realize the automated assessment of the levels of epiphysis of distal radius and ulna by support vector machine （SVM）. Methods The X-ray films of the left wrist joints were taken from 140 teenagers aged from 11 to 19 years old as training samples. The levels of epiphysis of distal radius and ulna were divided into five developmental levels. Each level contained 28 samples. Another 35 cases were selected as independent verifying samples. SVM classification models of the five developmental levels of epiphysis of distal radius and ulna were established. The internal cross validation was made by leave one out cross validation （LOOCV）, while the external validation was made by histogram of oriented gradient （HOG）, and then the accuracy （PA） of testing results was calculated, respectively. Results The PA of SVM, LOOCV and HOG of distal radius epiphyseal level were 100%, 78.6%, and 82.8%, respectively; whereas the PA of SVM, LOOCV and HOG of distal ulna epiphyseal level were 100.0%, 80.0% and 88.6%, respectively. Conclusion The SVM-based automatic models of the growth stage of distal radius and ulna appear to have certain feasibility, and may provide a foundation for software development of bone age assessment by forensic medicine.

Key words: forensic anthropology, epiphyses, ulna, radius, support vector machine