[Anatomo-functional properties of the vertebral axis].

The mechanics of the 3 segments of the vertebral column can be explained in the light of the existence of a real vertebral tripod; the modalities of the function of the three vertebral portions and of zones of transition, as well as the functional meaning of some vertebral structures or their annexes are explained. The author finally studies the vertebral curbs and denies them any value of increasing resistance or elasticity; he considers them as a factor of weakness which expresses itself mechanically by a compounded flexion to which the basical structure of the vertebral tripod and its bony, ligmentous and muscular annexes is opposed.