A grooved slot is provided in a bone fixation device for osteosynthesis that permits adjustment of the bone fixation device relative to the bone, before the bone fixation device is finally fixed to the bone. The grooves are formed on the two longitudinally extending, facing walls of the slot, with the grooves on a first side wall of the slot having a vertical displacement of exactly one-half pitch relative to the grooves on the second, opposite side wall of the slot.