Abstract: A distal aiming device adapted to be connected to an x-ray apparatus is independent of the type of x-ray apparatus being used. A nail holding mechanism detachably receives the proximal end of an elongated locking nail. The locking nail is held approximately in parallel with an elongated aiming head retaining mechanism which for its part is fitted on a holding arm capable of displacement about the axis of the locking nail being held in the nail holding mechanism. The aiming head retaining mechanism carries an aiming head and is capable of displacement in a direction approximately in parallel with the axis of the nail being held in the nail holding mechanism. An adjusting pin is adapted to be accommodated by the aiming head in a direction normal to the axis of the locking nail.