Prosthetic intervertebral discs (100) are described. The subject prosthetic discs include upper and lower endplates (110, 120) separated by a compressible core member (130). The subject prosthetic discs exhibit stiffness in the vertical direction, torsional stiffness, bending stiffness in the saggital plane, and bending stiffness in the front plane, where the degree of these features can be controlled independently by adjusting the components, construction, and other features of the discs.
