A medical device for fixing bone parts or for fixing stabilizing elements to bone parts. A rigid outer tube is provided with at least two opposed recesses on the side that is positioned in the bone. A second inner tube is accommodated in the rigid outer tube. The inner tube is provided with at least two strips extending in the longitudinal direction of the inner tube on the side that is positioned in the bone. The medical device is provided with a device for loading the inner tube in the axial direction, in such a manner that a pressure force is exerted on the strips, which pressure force causes the strips to bend outwards through the recesses.
