A spinal implant has a bone plate with a bone contacting surface and an opposite upwardly facing surface and at least one opening with a groove formed around an inner circumference of the opening. The groove has an axially spaced upper and lower surface. A bone-anchor or bone screw is capable of being accommodated in the opening between the groove and the bone contacting surface. A split-ring is mounted in the groove. The split-ring is sized to expand upon insertion of the anchor element into the opening and to come into direct contact with a head of the bone anchor to hold the bone anchor in the opening. The split-ring has an upper surface and a lower surface for respectively engaging the upper and lower surface of said groove, wherein the split-ring has a variable width so as to optimize its flexibility.