Changes in the foramen magnum axis during human foetal life

Abstract

The present findings showed that in early embryonic life the foramen magnum plane has a direction, more like that found in most animals in the sagittal plane due to the cervical flexure found at this early developmental period. Gradually during the foetal period the inclination of the foramen magnum plane changes to a more perpendicular relationship with the trunk preparing for a future erect posture. It was thought that the most important factor in this change of inclination is the rapid growth of the cerebral cortex. The study was carried out in order to see if possible changes in axial inclination of the foramen magnum axis in the sagittal plane can partly explain the changes in the cephalic flexure during foetal life. The material consisted of 38 selected human foetuses and 4 skulls of newborn babies.