Contribution to the clinical anatomy of the vertebral column. Considerations on the stability and the instability at the height of the "vertebral units".

Based on the findings with human cadaver material and the literature data, the concept of "vertebral unit" is discussed as a basic morphofunctional and pathogenic unit of the vertebral column. The vertebral structures collaborating to the stabilization of the vertebral units are described and a review is made of the possibilities of installation of a vertebral instability. An attempt is made to define the vertebral stability and instability.