Abstract: The skeletal age as a biological age of humans is a more accurate indicator for assessment of growth and development. In order to study the correlation between skeletal age and the indices of growth and development, we took the antero-posterior knee radiographs and got 23 indices of anthropometry of 2046 (male, 1061; female, 985) Han children and youths aged 6-23 years who were born in Kaiyuan County and in good health at the time of examination and menarcheal age was investigated for girls.
The results indicate that the time of epiphysis-diaphysis fusion of male of the inferior end of femur, superior end of the tibia and fibula is at 18.7, 21.1 and 19.5 years and female 17.7, 18.7 and 17.5 years, respectively.
The time of epiphysis-diaphysis fusion of the long bones forming knee joint correlates positively with body weight, sitting height etc. in boys and girls and with menarcheal age in girls. These are especialy true for the inferior end of femur and the superior end of fibula.

Key words: Epiphysis-diaphysis fusion; Kaiyuan county; Children and youths