Radiographic determination of developmental age in fetuses and stillborns.

The gestational age and/or viability of a fetus can become an important forensic issue. Several investigators have produced linear regression formulas based on crown-heel length (CHL), crown-rump length, or body diameters to determine gestational age. This study re-examines the relationship between fetal long bone length and CHL and tests a method of estimating CHL, and therefore gestational age, from radiographic measurements of the major long bone diaphyses. The results are compared with data based on dry bone measurements. Data from 252 cases confirm a strong correlation between all long bone lengths and CHL (> or = r = .9063; p < 0.01). Long bone length means for each CHL group are presented, as well as regression formulas for estimating CHL from radiographic measurements of the long bone diaphyses. The findings correspond closely with results based on a European sample, thereby validating that reference population as a normative sample for fetal analysis in the United States. The radiographic method can be used in instances where skeletal preparation is impossible or undesirable.