Quantitative anatomy of the ilium's primary ossification center in the human fetus.

With no sex and laterality differences, the best fit growth dynamics for the ilium's primary ossification center was modelled by the following functions: y = - 63.138 + 33.413 × ln(CRL) ± 1.609 for its vertical diameter, y = - 59.220 + 31.353 × ln(CRL) ± 1.736 for its transverse diameter, y = - 105.681 + 1.137 × CRL ± 16.035 for its projection surface area, and y = 478.588 + 4.035 × CRL ± 14.332 for its volume. The shape of the ilium's primary ossification center did not change over the study period, because its transverse -to- vertical diameter ratio was stable at the level of 0.94 ± 0.07. Conclusions The size of the ilium's primary ossification center displays neither sex nor laterality differences. The ilium's primary ossification center grows logarithmically with respect to its vertical and transverse diameters, and linearly with respect to its projection surface area and volume. The shape of the ilium's primary ossification center does not change throughout the examined period. The obtained quantitative data of the ilium's primary ossification center is considered normative for respective prenatal weeks and may contribute to the prenatal ultrasound diagnostics of congenital defects.