All-around surgical approach with ensured accuracy. The x-coordinate is set on both axes before mounting, which assures fast and correct positioning when fitting the arc to the frame. Leksell® Multi Purpose Stereotactic Arc with counter scale is designed to allow the surgeon to select any desired trajectory to the predetermined target, regardless of the patients position, when using Leksell Coordinate Frame G. Thanks to the counterscale the accuracy is further ensured when mounting the arc. Leksell® Multi Purpose Stereotactic Arc with counter scale can easily be mounted onto the frame in either A-P or lateral orientation. Lateral orientation is most commonly used, but the A-P orientation is especially useful for the implantation of depth electrodes in lateral targets. The unique option to attach several sliding carriers on the arc in combination with the center-of-arc principle allows the surgeon to simultaneously reach and/or observe any selected target through two or more trajectories.