The invention concerns a device comprising at least a fixed element (2), secured to a vertebra, at least a mobile element (10), capable of moving relative to the or each fixed element, and at least an intermediate element (22) for articulating the mobile element relative to the fixed element. The intermediate element (22) is received in an internal volume of the mobile element % (10), and the fixed element (2) is received at least partly in an internal volume (26) of the intermediate element (22). Means are provided for securing, at least in translation, said intermediate element (22) to the fixed element (2), comprising the periphery of the substantially rigid outlet of the internal volume of the intermediate element.