Radiographic fetal osteometry: approach on age estimation for the Portuguese population

The estimation of gestational age (GA) on fetal remains can be an important forensic issue. Forensic specialists usually use reference tables and regression equations derived from reference collections, which are quite rare in what fetuses are concerned. Since these tools are mostly grounded on ultrasonographic measurements, which are known to differ from real bones measurements or are based on ancient literature, this study aimed the construction of tables and regression equations for the Portuguese population on the basis of diaphyseal bone length measurements (femur, tibia and humerus) of 100 fetuses of known GA, using post-mortem radiographs. There is a strong correlation between the longitudinal length of studied bones and GA; the femur exhibits the strongest correlation (r=0.969; p=0.000), followed by the tibia (r=0.966; p=0.000) and the humerus (r=0.963; p=0.000). Therefore it was possible to obtain regression equations and to build tables with reference values for each of the diaphysis analyzed.