A QUANTITATIVE STUDY ON THE SPATIAL AND TEMPORAL OSSIFICATION PATTERNS OF VERTEBRAL CENTRA AND NEURAL ARCHES AND THEIR RELATIONSHIP TO THE FETAL AGE

A double-staining technique on 37 human embryos and fetuses (crown-rum p length, CRL, between 38 and 116 mm) has been performed to study the ossification patterns of the vertebral column. Different growth sequen ces for centra and neural arches were observed. The survey of ossified centers suggested it was possible to relate significantly their appea rance with the CRL. On the basis of already known data defining the de velopmental age in relationship to the latter parameter, we suggest th eir numerical evaluation as a further parameter for the assessment of the fetal age. Therefore, we have worked out a table that may be used either to determine the normal fetal growth, or when other parameters cannot be relied upon (i.e. in morphological diseases) for this aim.