Artificial disc devices (10) are disclosed that restore correct anatomical intervertebral spacing for damaged discs while maintaining a substantially normal range of biomechanical movement for the vertebrae between which they are implanted. The disc devices (10) include center bearing (12) and outer or annular bearing portions (14) with the center bearing portion (12) including generally axially extending locating surfaces (16 & 18) which cooperate with the facing vertebral surfaces to resist migration. The outer bearing portion (14) is for load bearing or load sharing with the center bearing portion (12) and includes surfaces (28 & 32) that extend radially toward the periphery of the vertebrae so that subsidence about the center bearing portion (12) is minimized. Alternate forms of the disc devices include one with an axially enlarged center ball bearing (92) having an annular ring bearing extending (82) thereabout and another having upper and lower plate members (20 & 22) with a central bumper member (36) and a surrounding resilient annular member (14) therebetween.
