Medical fastening device and medical device

A medical fastening device for an electromagnetic sensor, the fastening device comprising:

• a clamping element and
• a sensor mount, wherein the clamping element comprises a counterpiece and a pressing piece movable relative to the counterpiece, wherein the counterpiece has a lateral opening, which frees a free mounting area, wherein the counterpiece encloses the mounting area at least as a partial frame, wherein the counterpiece has a depression, which points towards the mounting area and which is arranged opposite the pressing piece, wherein the counterpiece is provided with an opening arranged opposite the depression, and wherein the pressing piece is movable in the opening in the direction of the depression of the counterpiece, wherein the counterpiece is configured as a one-piece, circumferentially partially open strap with two cheeks, which form end faces facing each other and have a finite distance from one another, wherein the circumferentially partially open strap with two cheeks has an outer contour with planar surfaces.