Abstract: An intervertebral connection device having a rigid osteosynthesis plate adapted to cover outer faces of at least two consecutive vertebrae at least partially. The plate includes an anterior face and an opposite posterior face. The posterior face is positionable against outer faces of at least two consecutive vertebrae. The plate further includes at least one pair of through bores each adapted to receive an anchoring screw arranged to anchor the plate on a vertebrae. The anchoring screws each includes a screw head. An anti-extraction device is adapted to prevent extraction of the anchoring screws. The anti-extraction device is mounted on the anterior face of the plate and acts as stops for the screw heads of the anchoring screws. The anti-extraction device includes at least one mobile flap mounted on the plate by a guide device.