Abstract: A bone screw (1) has a screw head (2), a screw tip (11), and a shaft (5) with a thread (8,14). The threaded segment (6,7) of the shaft (5) has a head-end, essentially cylindrical first shaft section (6) with minor diameter d.sub.1 (16), and a tip-end second shaft segment (7) that is connected with the first shaft segment (6) and which has a smaller minor diameter d.sub.2 (17). The thread (8,14) in the two shaft segments (6,7) has the same pitch (10,12).

Abstract: An osteosynthetic pressure plate includes a slot formation for receiving a bone-fixing screw which is adapted to be secured to a bone part which is to be mended. The slot is formed with an edge which includes an oblique portion or ramp having an inclination such that when it is engaged by the underside of a head portion of a bone-fixing screw there will be a displacement of the pressure plate in a direction to move the ramp portion away from the fixing screw and to cause the plate to apply a pressure to hold the bone parts in tight engagement. The plate is advantageously useable with screws having heads of spherical form or conical form, for example.

Abstract: An osteosynthetic pressure plate includes a slot formation for receiving a bone-fixing screw which is adapted to be secured to a bone part which is to be mended. The slot is formed with an edge which includes an oblique portion or ramp having an inclination such that when it is engaged by the underside of a head portion of a bone-fixing screw there will be a displacement of the pressure plate in a direction to move the ramp portion away from the fixing screw and to cause the plate to apply a pressure to hold the bone parts in tight engagement. The plate is advantageously useable with screws having heads of spherical form or conical form, for example.