Deformities of the leg and ankle may result from growth abnormalities of the tibia and fibula. The appearance of the secondary ossification center and growth plate closure of the tibial and fibular epiphyses, and the pattern of closure of the epiphyses, were observed in a different age. Normal radiographs were reviewed in one hundred and fifty patients at age from two days after birth to 20 years, who were injured on the contralateral leg, at Wonju Medical College, Yonsei University from Feb., 1980 to May, 1984. The results were as follows: 1. The time of the appearance of secondary ossification center and the closure of growth plates; The proximal tibial epiphysis usually forms secondary ossification center at birth to second postnatal months, the physeal closure occurs from 13 year and 11 months to 18 year 3 months in male, from 13 year 4 months to 15 year 5 months in female. The secondary ossification center of the distal tibial epiphysis appears from 8th postnatal months to one year, and physeal closure occurs from 15 years to 17 year and 4 months in male, from 15 year 2 months to 16 year 8 months in female. The secondary ossification center of the tibial tuberosity appears from 9 year 3month to 12 year 2 months, and closure occurs from 16 year 3 months to 18 year 7 months inmale, from 14 year 10 months to 19 year 1 months in female. The proximal fibular epiphysis forms secondary ossification center from 2 year 5 months to 5 year 4 months, closure occurs from 15year 8 months to 17 year 4 months in male, from 14 year 9 months to 16 year 9 months in female. The secondary ossification center of the distal fibular epiphysis appears from 2 year 5 months to 3rd years, and closure occurs from 13 year 11 months to 17 year 6 months in male, from 13 year 4 months to 16 year 7 months in female. 2. The growth and the pattern of the closure of growth plates of the tibia; The proximal tibial epiphysis is elliptic for the first 3 years of life. The epiphysis is slightly conical centrally as it extends toward the tibial spines, and becomes more prominent from 8 years to adolescence. The closure of the proximal tibial growth plate occurs initially along the anteromedial aspect of the tibia and tibial tuberosity during 12 years and proceeds posterolaterally. Complete closure of the proximal tibial physis occurs about from 13 years to 18 years. The secondary ossification center of the distal tibial epiphysis is oval in shape initially, becomes thicken medially by 3rd year of life, then the tibial plafond is valgoid, and becomes horizontal at age 10 approximately. The distal epiphysis of tibia unites first at about 13 years, starting centrally and proceeding toward anteromedial portion. And the posterolateral portion unites finally by about 15 to 17 years. The tibial tuberosity develops a secondary ossification center by 7 to 9 years, usually in the most distal region, and gradually elongates and extends toward the secondary ossification center of the proximal tibia.From about 12 years, the tuberosity epiphyseal center fuses with the proximal tibial center, and the fusion with the tibial metaphysis extends distally, the tuberosity physis closes completely from about 15 to 19 years. 3. The growth and development of the tibia, fibula and ankle; The growth of the proximal tibial and the distal fibular epiphyses play an important role of the growth rate in lower extremities unber ten years. The distal tibial growth plate inclines laterally and distally prior to the first year of life, the inclination is on the decrease and it finally horizontal at about 12 years. The distal tibia talus angle is about 90° prior to the age one year, becomes mildly valgoid by 12 years.