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. The inclination of the ramp and the configuration of the walls bounding the slot of the pressure plate are such that there will be a uniform and even shifting of the plate having the slot when the ramp portion of the walls bounding the slot is engaged by the screw head to cause the desired displacement of the pressure plate in order to displace the bone fragment toward tighter engagement with the adjacent bone fragment and into pressure engagement therewith.
A method of forming a slot for an osteosynthetic pressure plate using a cutter having a rounded end and an ordinary cutter of cylindrical configuration comprising, advancing the rounded cutter into the plate surface first at an angle substantially normal to the surface and thereafter inclining the rounded milling head to one side while cutting into the plate to form a groove with an inclined wall on one end, removing the rounded milling head and inserting a cylindrical cutter into the groove and advancing it in a direction normal to the plate to cut a slot through the plate extending at a spaced location from each end of the walls cut by the rounded milling head and intersecting the inclined hemispherical surface formed by the rounded miller, and thereafter moving the cylindrical cutter in a longitudinal direction to elongate the cut slot.
Claim 2
Independent Claim
142 words
A method of forming a slot for an osteosynthetic pressure plate using a cutter having a rounded end and an ordinary cutter of cylindrical configuration comprising, advancing the rounded cutter into the plate surface first at an angle substantially normal to the surface and thereafter inclining the rounded milling head to one side while cutting into the plate to form a groove with an inclined wall on one end, removing the rounded milling head and inserting a cylindrical cutter into the groove and advancing it in a direction normal to the plate to cut a slot through the plate extending at a spaced location from each end of the walls cut by the rounded milling head and intersecting the inclined hemispherical surface formed by the rounded miller, and thereafter moving the cylindrical cutter in a longitudinal direction to elongate the cut slot.