The invention relates to a medical navigation marker device (1； 2； 3) comprising a light reflector, characterised in that the reflector features a marker pattern (11, 12, 13； 11, 12, 13, 14, 15, 16； 27, 28； 34, 37； 35, 37) having the following features:—the marker pattern (11, 12, 13； 11, 12, 13, 14, 15, 16； 27, 28； 34, 37； 35, 37) points in more than one spatial direction；—the marker pattern (11, 12, 13； 11, 12, 13, 14, 15, 16； 27, 28； 34, 37； 35, 37) comprises at least one moire pattern (11, 12, 13； 27； 37) which points in more than one spatial direction； and—the marker pattern (11, 12, 13； 11, 12, 13, 14, 15, 16； 27, 28； 34, 37； 35, 37) comprises a face identification pattern (14, 15, 16； 25, 26； 34； 35) which identifies the face of the marker being viewed from a particular spatial direction. The invention also relates to a combination of a medical marker device (1； 2； 3) and a medical navigation system (43) which uses the marker device (1； 2； 3) as a spatial position and/or orientation marker, and to the use of a medical marker device (1； 2； 3) for providing guidance to a user of a medical navigation system (43) by evaluating the spatial position and/or orientation information provided by the marker device.
