A prosthesis for a vertebral column has an upper part (10) for attachment to anupper vertebrae, a lower part (12) for attachment to a lower vertebrae and a middlepart (11) located between the upper and the lower parts, wherein the upper parthas a lower surface portion with a first radius of curvature, the middle part hasan upper surface portion with a second radius of curvature and a lower surfacewith a third radius of curvature and the lower part has an upper surface with a fourthradius of curvature. The centre of the radius of curvature for at least two surfacesis offset rearwardly with respect to a central vertical axis (13) through theupper and lower vertebrae and/or the upper and lower parts. Also defined is devicefor linking bones, in the form of a band with attachment portions having a numberof filaments that provide zones conducive to cellular growth as well as a methodof modelling a prosthesis and a process for analysing performance of a prosthesis.