Bone microarchitecture is receiving increasing attention in the
assessment of the biomechanical properties of bone. While it is
well characterized in normal and pathologic human subjects,
few quantitative data are available in human fetal development.
In this paper, quantitative parameters of bone microarchitecture
in developing human bone are reviewed from the literature and
supplemented by new data from the femoral metaphysis of human
fetuses. The samples were imaged using synchrotron radiation
3D micro-CT and processed using customized analysis
methods. This technique provides 3D model independent morphometric
parameters, anisotropy, connectivity and geometry
characteristics, as well as information on mineralization.
The morphometric parameters obtained on fetal vertebrae and
femurs evidenced a dense trabecular structure as compared
to that of young adults. The histomorphometric and the 3D micro-
CT analysis were consistent to show a significant increase
of trabecular bone volume with gestational age. Trabecular
bone was found isotropic in vertebral bodies and
anisotropic in femoral metaphysis, demonstrating a radial
growth in vertebrae, and a longitudinal spreading out in long
bones such as the femurs. Trabecular thickness in the mature
bone of vertebral body and femoral metaphysis was around
100 μm, which was in agreement with histomorphometric evaluation.
In the femoral metaphysis, three-dimensional analysis
confirmed the thickening of trabeculae with the distance to
the growth plate, and an estimated rate of thickening around 3
μm/day previously obtained in histomorphometry. The 3D network
was highly connected, and our new geometrical analysis
technique showed a strong prevalence of rod structure as
compared to the plate structure in cancellous bon
