A device for bracing the vertebrae of the human spinal column, having at least one pedicle screw with a head that is formed so as to be at least partially spherical and that is received into an at least partially spherical mounting area of a pedicle head, wherein the pedicle head has a centric recess which includes comprises the mounting area and a slit for receiving a rod that is arranged transversely with respect to the centric recess, as well as an internal thread which is formed inside the centric recess opposite the mounting area and inside of which a safety screw for clamping the rod is arranged, wherein the safety screw is provided with an anti-rotation device at that side that is facing towards the rod.