A prosthesis replaces all or a portion of a cephalad portion of a natural facet joint (i.e., an inferior articular process) on a vertebral body. The prosthesis has a prosthesis body that accommodates fixation to the vertebral body at or near a pedicle and without support by a lamina. The prosthesis also has an artificial facet joint structure carried by the prosthesis body adapted and configured to replace all or a portion of a cephalad portion of a natural facet joint.