An artificial disc having a pair of opposing plates for seating against opposing vertebral bone surfaces, separated by a spider spring having a plurality of spring arms extending radially from a central hub. Various spring arm embodiments disclosed include spring arms that are straight, bowed, grooved, wavy, thinning, or thickening; and spring arms with parallel sides, radially outwardly diverging sides, or radially outwardly diverging and curving sides. Various spider spring embodiments disclosed include spider springs with central hubs that are solid, bored, have curvate sockets, or have semispherical protuberances. Various plate embodiments disclosed include plates having, on inwardly facing surfaces, a curvate socket, a semispherical protuberance, a circular recess, or a flat surface. The spider springs are disposable between the plates, through various disclosed couplings, so that the plates compress, rotate and angulate freely relative to one another, enabling the artificial disc to mimic a healthy natural intervertebral disc.