A fixation clamp for use in an external fixation clamp has a clamping assembly having a reception to accommodate a fixation element. The clamp has a locking element extending through the clamping assembly for blocking the position in a defined angular position. A washer is arranged between the locking element and a central opening of the clamping assembly having a cutout extending radially from the through opening such that the washer is mountable and demountable in a radial direction to a locking element longitudinal axis. The cutout has a smaller distance between its sidewalls then the diameter of the through opening. The locking element has circular cross-section below its head portion adapted to fit through the through opening of the washer but larger than the opening of the cutout and has at least one pair of parallel beveled surfaces spaced closer than the distance between sidewalls of the washer cutout.