The present invention is directed to a major long bone ring implant for
insertion into an implantation space formed across a spinal disc between
two adjacent vertebral bodies of the spine. The implantation space has a
wall portion, lip, or ridge with a flat portion for abutting the leading
end of the bone ring implant. The bone ring implant has a leading end and
a trailing end connected by opposed sides. The leading end has a straight
cut portion. The opposed sides have portions that are preferably straight
and at a 90.degree. angle to the straight cut portion of the leading end
to produce straight portions that are outwardly facing. The bone ring
implant may be machined from a single bone or manufactured from a
composite of cortical fibers, filaments, or particles. The bone ring
implant may be used in combination with lockable screws, and preferably
screw locks each preferably made of cortical bone or of a bioresorbable
material.