A reinforcing implant for the lamina of a vertebra includes a transverse support, one anchoring device for the right-hand side and one anchoring device for the left-hand side of the lamina of the vertebra. An expansion element with a guide device and cheek elements is provided, the cheek elements being mounted to be longitudinally movable along the guide device. Bearing surfaces for the lamina are formed on outer faces of the cheek elements directed away from each other, and a return stop for the cheek elements is provided. At least one of the cheek elements is provided with an aligning device for modifying the orientation of its bearing surface relative to the guide device. In this way, a secure anchoring of the reinforcing implant on the resected surfaces produced during a laminectomy can be achieved, with precise adaptation of the reinforcing implant to the actual anatomical conditions following the laminectomy.