Morphological assessment of craniovetebral junction development in the prenatal period.

Background: Because of numerous abnormalities of craniovertebral junction development observed in the prenatal period, the region has been studied thoroughly in order to elucidate the mechanism of axial differentiation, dependence of vertebral morphology on the development of ossification centers and the mechanisms regulating the dynamics of growth. AIM: Analysis of morphological changes of the craniovertebral junction taking place during the prenatal period by quantitative assessment of some developmental changes such as growth rate, sexual dimorphism, interdependence of the analyzed parameters, taking into consideration the variable geometry of the studied area. Material/Methods: The study was carried out on 48 fetuses (22 male, 26 female) of 86-212mm crown-rump length (CRL) range. The applied methods included: anthropometry, precise measurements, as well as trigonometric calculation of angles. Results: All the investigated parameters demonstrated a strong, statistically significant correlation with CRL. No statistical significance of sexual dimorphism and differences between left- and right-sided measurements was demonstrated. The development rate indexes for the height of C1,C2 posterior vertebral arches, unlike those for the transversal dimensions of C1,C2 posterior vertebral arches, decrease after 5 months of gestational age. Little variability of the angles determined by geometrical reconstruction evidences close interdependence in the development of the analyzed craniovertebral junction elements. Conclusions: Geometrical configuration of the craniovertebral junction during the fetal period is constant, with growth isometry preserved throughout intrauterine development. The occipital bone and Cl, C2 cervical vertebrae are closely correlated according to structural and functional dependences.