Patent ID: 8226724

Claim:
A prosthetic device comprising: a superior vertebral plate; a ball element having an upper spherical surface and an undersurface, wherein the upper spherical surface is moveably secured within and, at least partially, conforms to a receiving cavity within the superior vertebral plate, a central cylinder comprising, a superior external segmented wall fixedly attached at one end to the undersurface of the ball element; and an inferior external segmented wall slidably engaged with the superior external segmented wall and fixedly attached at one end to a base ring, wherein the base ring comprises a central opening; an inner cylinder core within the central cylinder comprising, a superior inner segmented wall fixedly attached at or near a first end to the undersurface of the ball element; a first center post element fixedly attached at or near a second end of the superior inner segmented wall; an inferior inner segmented wall slidably engaged with the superior inner segmented wall and fixedly attached, at or near a first end, to a means for providing at least one degree of translational motion, wherein the means for providing at least one degree of translational motion is fixedly attached within the central opening of the base ring; a second center post element fixedly attached at or near a second end of the inferior inner segmented wall, between the first center post element and the undersurface of the ball element, such that the first and second center post elements inhibit the walls of the central cylinder and the inner cylinder core from separating; and an inferior vertebral plate slidably connected to the means for providing at least one degree of translational motion, such that when said device is implanted in a spine with the superior and inferior vertebral plates engaged with a first and second vertebra, said device forms a kinematic chain of connected, inseparable, articulating components between said first and second vertebra, wherein said device has means for providing at least one and up to three independent rotational degrees of freedom and additional means for providing at least one and up to three independent linear degrees of freedom.