Osteosynthesis plate system

An osteosynthesis plate system, comprising:

• a rigid, elongate plate member adapted to bridge and immobilize adjacent bones or bone segments by anchoring the plate to the bones using one or more bone screws, the member having a first, bone contacting surface and a second, non-bone contacting surface;
• a plurality of substantially circular screw holes extending through the member, each having substantially spherical seats and being adapted to seat bone screws;
• a plurality of bone-penetrating projections disposed on the first surface of the member;
• a plurality of bone screws, each having a threaded end opposite a substantially spherical head, each bone screw adapted to fit within a screw hole to anchor the member to bone;
• and
• locking means adjacent one or more screw holes for securing the bone screw to the member to inhibit axial and rotational movement of bone screws seated within the screw holes and engaging bone, the locking means being rotatably actuable, coplanar with and permanently disposed in the second, non-bone contacting surface of the plate member and being integral with the plate member to lock the bone screws.