A medical instrument contains at least three navigation markers which in each case have at least one marker element which can be captured by a camera in a camera image in an identifiable manner. The navigation markers are each attached to the instrument at an attachment point lying on a first straight line. At least one of the navigation markers contains at least three marker elements arranged at a known distance on a second straight line associated with the respective navigation marker. Moreover, a medicine system and a method display a position of a position marker spatially correlated with the medical instrument.