Patent ID: 8623019

Claim:
A spinal bone plate system comprising: an elongate plate member; a plurality of throughbores of the plate member each extending along a respective bore axis through the plate member; a plurality of bone anchor members each having a non-threaded head end for driving the bone anchor members into spinal bones and a threaded shank depending from the head end with the non-threaded head end being radially enlarged relative to the threaded shank; at least one rigid pivot base for being received in one of the throughbores and having a rigid non-threaded wall and a through opening about which the non-threaded rigid wall extends and which is configured to receive one of the bone anchor members extending therethrough with the non-threaded radially enlarged head end of the one bone anchor member seated against the non-threaded rigid wall in the through opening in non-threaded engagement therewith so that the non-threaded rigid wall extends about the head end and between the head end and the plate member to completely space the head end from the plate member; a through aperture in the wall of the pivot base extending laterally therethrough and aligned with the head end of the bone anchor when the head end is seated within the through opening of the pivot base; at least one pivot member extending in the through aperture of the pivot base wall such that the seated bone anchor head end blocks laterally inward movement of the at least one pivot member, the at least one pivot member extending between the pivot base and the plate member to pivotally mount the pivot base to the plate member for pivoting relative thereto to allow pivoting of the rigid pivot base and the associated bone anchor member relative to the plate member with the head end of the bone anchor member seated in the pivot base opening and the bone anchor member driven into a spinal bone; floor portions of the elongate plate member that extend laterally transverse to the bore axis inwardly into the one throughbore on either side thereof to define a narrow section of the throughbore; lower surface portions of the rigid pivot base configured for being supported on the inwardly extending floor portions of the plate member upon pivoting of the rigid pivot base in the one throughbore; and an inner side wall portion of the plate member extending along the throughbore adjacent to the through aperture of the pivot base wall such that the inner side wall portion blocks laterally outward movement of the pivot member.