Ossification of the vertebral column in human foetuses: histological and computed tomography studies

Abstract

There is no agreement in the literature as to the time of the onset and progress ofthe vertebral column ossification. The aim of the present study was to determinethe precise sequence of ossification of the neural arches and vertebral centra.Histological and radiographic studies were performed on 27 human foetuses agedfrom 9 to 21 weeks. It was found that the ossification of vertebrae commencesin foetuses aged 10 and 11 weeks. Ossification centres appear first for neuralarches in the cervical and upper thoracic vertebrae and by the end of 11th weekthey are present in all thoracic and lumbar neural arches. In the vertebral centrain foetus of 10 weeks ossification was found in the lower 7 thoracic and firstlumbar vertebrae. By the end of 11th week ossification is present in the lower4 cervical, all thoracic, all lumbar and 4 sacral vertebral centra. The study indicatesthat ossification of the neural arches proceeds in the craniocaudal direction,whereas in the vertebral centra it progresses from the lower thoracic vertebraeinto both directions. Different shapes of ossification centres were also described.