Estimation of age from the femur of Japanese cadavers

This study was designed to estimate the age at the death of cadavers by histomorphometry of the femur. Samples from 72 Japanese males from 43 days to 92 years old and 26 females from 2 to 88 years old were used. The thickness of sections was adjusted to 50-70 microns by grinding with sandpaper. The sections were not any decalcified. They were stained with Villanueva's bone staining powder and thionin dye. The microradiographs of the sections were obtained by a soft x-ray apparatus. The area, length, width, and perimeter of the perfect osteon and haversian canal were measured. The type II osteon number, osteon fragment number, and area of triangle were also determined. These parameters were examined by an image analyzer. The parameters of the osteon showed a high correlation coefficient with age (magnitude of r > or = 0.77), whereas those of the haversian canal were low (magnitude of r < or = 0.11). All parameters were subjected to multiple regression analysis for producing a multiple regression equation of age estimation. For the stepwise selection method, the perimeter of osteon, length of the haversian canal, and osteon fragment number were selected for the equation. Their multiple r2 and standard error of estimation were 0.8874 and 6.39, respectively. For the forward selection method, in addition to the above items, three parameters, the length of osteon, area of triangle, and width of osteon, were selected. Their multiple r2 and standard error of estimation were 0.9484 and 4.884, respectively. Bone staining was useful to clarify the demarcation between osteon and fragment, leading to increased accuracy of age estimation. However, precisely estimating age for the entire range from birth to 90 years was difficult.