A vertebral plate system and associated method minimizes the number of required multiple configurations and sizes of hardware on hand during surgery for repair, stabilization or fusion of bone segments. A novel aspect of the invention is a resilient split ring that cooperates with angled contact surfaces in a plate for allowing convenient and fast dynamic locking between the plate and a bone screw. In another aspect of the present invention, a screw or similarly elongated fastener having a generally spherical or part-spherical head with a section of helical threads is configured in a generally horizontal band and positioned around a maximum-diameter section of the head. The screw is loosely retained to a first structure by a snap-ring formed from a ring of elastic material having a slot cut so that the ring is a "C" ring. The ring is seated on an annular shoulder formed in a through-hole in the first structure. The section of the through-hole above the shoulder tapers inwardly in an upward direction to a minimum diameter that is smaller than the outside diameter of the ring when the ring is in an unstressed state. The inner diameter of the ring has an edge that is adapted to cooperate with and ride in the threads on the screw head.