u201c x u201d corresponding to core 200 sliding along engaging surface 404 2 translation in the direction indicated by line u201c y u201d corresponding to axial compression of core 200 3 translation in the direction indicated by line u201c z u201d corresponding to core 200 sliding along engaging surface 404 4 rotation about an axis indicated by line u201c x u201d corresponding to compression of one side of core 200 5 rotation about an axis indicated by line u201c y u201d corresponding to core 200 rotating upon engaging surface 404 and 6 rotation about an axis indicated by line u201c z u201d corresponding to compression of one side of core 200 alternatively stated if an axis of the implant is defined as extending through an implant of the invention from a first adjacent bone to a second adjacent bone the implant would enable relative motion of the first and second adjacent bones with respect to in an alternative embodiment shown in fig5 and 6 core 200 a includes first and second segments 202 a 206 a separated by an inflection region 210 a that is substantially narrower than flanking segments 202 a 206 a and thus bends to enable an angular displacement of segments 202 a 206 a and accordingly enables an angular relative displacement of engaging surfaces 204 a 208 a fig6 illustrates a cross section of the implant 100 of fig5 taken through projections 308 and 408 at least a portion of core engaging surface 404 a is configured as a curved smooth surface upon which a mating region of curved smooth surface of second engaging surface 208 a of flexible core 200 a may slide in the illustration a curved slidable portion of core engaging surface 404 a is recessed within second support component 400.