Abstract: This invention is an implantable device and system that allows post-operative, non-invasive adjustment of members of the skeletal system. It includes extension-resisting members and a compression-resisting member that connect members of the skeletal system. Post-operative, non-invasive adjustment of the tensions, lengths, widths, and/or torsions of the extension-resisting members changes the relative movement, position, or both movement and position of members of the skeletal system. The compression-resisting member may act as a fulcrum. This invention can help to pioneer the evolution of “smart” orthopedic devices that adjust skeletal biodynamics to address changing clinical needs and changes in patient activity over time. Some promising applications include: dynamic stabilization of the spine; correction of scoliosis; and bone elongation.