Abstract: The present invention relates to a system for osteosynthesis at the vertebral column, in particular for stabilizing spinal segments including at least one rodlike connecting element (14) and at least two retaining units (12). Each retaining unit can be anchored to a spinal segment with a tuning-fork-shaped head, (15) the two limbs (16, 17) of which delimit an approximately U-shaped receptacle (18) for the connecting element (14) A clamping screw (19) can be screwed into the receptacle (18) to fix the connecting element (14) between the two limbs (16, 17) of the tuning-fork-shaped screw head (15) The floor (22) of the receptacle (18) has a concave shape to correspond to a swivel-bearing element (23) disposed between the floor (22) of the receptacle (18) and the connecting element (14) The element (24) has a bearing surface (24) faces the floor (22) of the receptacle (18) and, has a complementary convex curvature.

Abstract: A metal fixation element is disclosed for receiving a plastic socket component of an artificial hip joint. The fixation element includes a frontal region which faces the pelvic bone. The frontal region has a central bore, with a screw thread to receive an insertion tool. The element also includes at least one conically tapering wall spaced from the frontal region. A self-tapping screw thread on the outer surface of the tapering wall provides for cementless fixation of the element in the pelvic bone. There is further provided an additional conically tapering wall between the frontal region and the first conically tapering wall. Three apertures are located in the frontal region. A cover element is rotatably mounted within the fixation element closely abutting the frontal region. The cover element has three equally spaced openings separated by continuous positions for selective opening and closing of the three apertures in the frontal region.