An intervertebral disk prosthesis for the total replacement of an intervertebral disk of the cervical or lumbar spine, the prosthesis comprising: an upper plate having on its upper surface upwardly projecting formations anchoring it to an upper vertebra and a concavity on its lower inner surface surrounded by an edge; a lower plate having on its lower surface downwardly projecting formations anchoring it to a lower vertebra and a flat upper inner surface surrounding a guide groove having flank surfaces extending front-to-back; and an intermediate sliding plate between the upper and lower plate having on its upper surface a convexity surrounded by an annular surface and engaging the concavity on the inner surface of the upper plate, and on its flat lower surface a guide ridge having flanks extending front-to-back wherein the flanks of the guide ridge are in contact with the flank surfaces of the guide groove wherein the end of the guide ridge has a larger dimension than a stem of the guide ridge to prevent a slip out of the guide ridge out of the guide groove, wherein the stem is directly connected to the flat lower surface of the intermediate sliding plate and the guide groove of the lower plate houses the guide ridge of the intermediate sliding plate permitting the guide ridge to slide front-to-back within the guide groove, wherein the guide ridge is of at least semi-elastic composition and comprises at least one open slit so that the guide ridge can be elastically deformed by compression and fitted into the guide groove, wherein the convexity of the intermediate sliding plate, the concavity of the upper plate and the surrounding annular surface of the convexity and the surrounding edge of the concavity permit limited extension, flexion, lateral bending to the right and left side, and axial rotation to both sides. an upper plate having on its upper surface upwardly projecting formations anchoring it to an upper vertebra and a concavity on its lower inner surface surrounded by an edge; a lower plate having on its lower surface downwardly projecting formations anchoring it to a lower vertebra and a flat upper inner surface surrounding a guide groove having flank surfaces extending front-to-back; and an intermediate sliding plate between the upper and lower plate having on its upper surface a convexity surrounded by an annular surface and engaging the concavity on the inner surface of the upper plate, and on its flat lower surface a guide ridge having flanks extending front-to-back wherein the flanks of the guide ridge are in contact with the flank surfaces of the guide groove wherein the end of the guide ridge has a larger dimension than a stem of the guide ridge to prevent a slip out of the guide ridge out of the guide groove, wherein the stem is directly connected to the flat lower surface of the intermediate sliding plate and the guide groove of the lower plate houses the guide ridge of the intermediate sliding plate permitting the guide ridge to slide front-to-back within the guide groove, wherein the guide ridge is of at least semi-elastic composition and comprises at least one open slit so that the guide ridge can be elastically deformed by compression and fitted into the guide groove, wherein the convexity of the intermediate sliding plate, the concavity of the upper plate and the surrounding annular surface of the convexity and the surrounding edge of the concavity permit limited extension, flexion, lateral bending to the right and left side, and axial rotation to both sides.