Morphometric study of the primary ossification center of the fibular shaft in the human fetus

PURPOSES: Precise morphometric data on the development of ossification centers in human fetuses may be useful in the early detection of skeletal dysplasias associated with delayed ossification center development and mineralization. The present study was performed to quantitatively examine the primary ossification center of the fibular shaft with respect to its linear, planar and volumetric parameters. MATERIALS AND METHODS: Using methods of CT, digital-image analysis (Osirix 3.9 MD) and statistics (Student’s t-test, Shapiro–Wilk, Fisher’s test, Tukey’s test, Kruskal–Wallis test, regression analysis), the size of the primary ossification center of the fibular shaft in 47 spontaneously aborted human fetuses (25 ♂ and 22 ♀) aged 17–30 weeks was studied. In each fetus, the assessment of linear dimensions (length, transverse diameters for: proximal end, middle part and distal end), projection surface area and volume of the fibular shaft ossification center was carried out. RESULTS: With no sex and laterality differences, the best fit growth dynamics for the primary ossification center of the fibular shaft was modelled by the following functions: y = − 13.241 + 1.567 × age ± 1.556 (R(2) = 0.94) for its length, y = − 0.091 + 0.063 × age ± 0.073 (R(2) = 0.92) for its proximal transverse diameter, y = − 1.201 + 0.717 × ln(age) ± 0.054 (R(2) = 0.83) for its middle transverse diameter, y = − 2.956 + 1.532 × ln(age) ± 0.090 (R(2) = 0.89) for its distal transverse diameter, y = − 69.038 + 4.699 × age ± 4.055 (R(2) = 0.95) for its projection surface area, and y = − 126.374 + 9.462 × age ± 8.845 (R(2) = 0.94) for its volume. CONCLUSIONS: The ossification center in the fibular shaft follows linear functions with respect to its length, proximal transverse diameter, projection surface area and volume, and natural logarithmic functions with respect to its middle and distal transverse diameters. The obtained morphometric data of the fibular shaft ossification center is considered normative for their respective prenatal weeks and may be of relevance in both the estimation of fetal age and the ultrasound diagnostics of congenital defects.