A polyaxial connector for spinal fixation systems has a lateral connector element having a first receptacle for a polyaxial connection to a spherical head of a pedicle screw and a second receptacle for a polyaxial connection to a spherical head of tulip that is configured to receive a connection rod clamped in the tulip by a locking element. A clamping piece is mounted in longitudinally-movable manner in the connector element between the receptacles. If the locking element is tightened, a pressure ram received in the tulip exerts a clamping force on the pedicle screw head, thereby fixing the connector element to the pedicle screw.