Age-related Histomorphometric Changes in Human Fetal Long Bones

• Main Author: Eleazer, Courtney D.
• Published: Trace: Tennessee Research and Creative Exchange 2007
• Subjects: Arts and Humanities
• Online Access: http://trace.tennessee.edu/utk_gradthes/124

The goal of this study is to investigate the age-related changes in histomorphometry among the six long bones of the human fetus. Histological studies have become increasingly important in distinguishing fragmentary human remains from non-human remains as well as estimating age at death in forensic cases. However, little work has been done with subadult material due to its distinct growth patterns and unique microscopic composition. This study attempts to provide a preliminary investigation into the potential of utilizing histomorphometry in the estimation of age at death of fetal remains. Microscopic methods may prove invaluable to the task of aging fragmentary remains that lack the characteristic features necessary for conventional metric methods that require the preservation of entire skeletal elements. Seven stillborn cadavers of known sex and gestational age (17-35 weeks) were the subjects of study. Thin sections were taken from the midshafts of the six long bones and examined under a light microscope. For each slide, a maximum of 111 measurements were taken: maximum sagittal medullary diameter (anterior-posterior), maximum transverse medullary diameter (medial-lateral), medullary area, maximum cortical thickness (taken at each quadrant), minimum cortical thickness (taken at each quadrant), and a maximum of 25 separate trabecular diameters per quadrant. The results of this research indicate that several histological measurements possess potential for predicting fetal age. Statistically significant correlations between both maximum and minimum cortical thicknesses and age were present for all six long bones. The humerus and tibia have the strongest correlations between cortical thickness and age, while the radius possesses the weakest correlation with age. The results of an ANCOVA employing age as a covariate indicate that fetal age is a significant linear predictor of trabecular thickness in all long bones except the radius. The values for trabecular thickness are significantly different among quadrants within the femur, tibia, humerus, and ulna. However, only in the humerus and radius does the rate of linear change in trabecular thickness with age differ by quadrant location. Future research conducted on a larger sample size is expected to determine the accuracy with which this method can be applied to fetal age estimation.