The present invention relates to a surgical tool (1) for use in guided surgery comprising a distal end portion having a functional element (10), a shank (23) on the opposite end of the tool (1), and a substantially circular cylindrical guide portion (45). The guide portion (45) is located between the functional element (10) and the shank (23) and has at least one visual marker (50). The at least one marker (50) comprises at least one recess which is finite in the circumferential direction such that, at the axial location of the recess a section (65) of guide portion (45) having outer radius r is maintained.
