Quantitative study of the primary ossification centre of the parietal bone in the human fetus.

Abstract

Detailed morphometric data concentrating on the development of primary ossification centres in human fetuses is critical for the early detection of developmental defects. Thus, an understanding of the growth and development of the parietal bone is crucial in assessing both the normal and pathological development of the calvaria. The size of the parietal primary ossification centre in 37 spontaneously aborted human fetuses of both sexes (16 males and 21 females) aged 18-30 weeks was studied by means of computed tomography, digital-image analysis and statistics. The numerical data of the parietal primary ossification centre in the human fetus displays neither sex nor laterality differences. With relation to fetal age in weeks, the parietal primary ossification centre grew in sagittal diameter according to the quadratic function: y = 16.322 + 0.0347 × (age)² ± 1.323 (R² = 0.96), in projection surface area according to the cubic function: y = 284.1895 + 0.051 × × (age)³ ± 0.490, while in both coronal diameter and volume according to the quartic functions: y = 21.746 + 0.000025 × (age)⁴ ± 1.256 and y = 296.984 + + 0.001 × (age)⁴, respectively. The obtained morphometric data of the parietal primary ossification centre may be considered age-specific references, and so may contribute to the estimation of gestational ages and be useful in the diagnostics of congenital cranial defects.