Abstract: The histological age changes that occur in the cortex of human long bones were measured by counting the number of osteon, osteon fragments, non-Haversian canal and the average of the relative thickness of lamellae in four selected 100 power visual fields in the peripheral part of the cortex in ground cross sections of the mid-shaft of the femur. Bar charts of age and bi-logarithmic line charts of age were derived from 35 specimens covering an age range from 5 years through 86 years. Significant correlations were found between the actual age and estimated age. About 80% of the estimated ages calculated from the regression formulas derived from these factors are within ±5 years of the actual ages and nearly 90% are within ±10 years of the actual ages. Synthetic method is used to estimate age by data of all of the 4 items. When this method was checked on 24 specimens, about 80% of the estimates fall within ±5 years of actual ages, the results are better than those by Kerley's method for Chinese specimens.

Key words: Bone age estimating; Femur; Histology