Patent ID: 6855152

Claim:
A device to be used in combination with a surgical navigation system for defining the position of a straight line determined by an operating surgeon within a three-dimensional coordinate system in an operating theatre, including: A) a body ( 1 ) having a surface ( 2 ) and at least three markers ( 3 ) emitting waves ( 19 ), positions of said markers being determined within the three-dimensional coordinate system by means of a position detector that is part of the surgical navigation system; whereby B) the body ( 1 ) comprises a laser ( 4 ) that emits a laser beam ( 5 ), directed away from the body ( 1 ), said laser beam having a geometrical central beam ( 6 ) and a wavelength in the visible range; and C) a position of the central beam ( 6 ) relative to the three-dimensional coordinate system may be calculated from the determined positions of the markers ( 3 ) by means of a computer that is also part of the surgical navigation system; and wherein D) the body ( 1 ) is a planar plate with a top surface ( 11 ) and a bottom surface ( 12 ); E) the laser beam ( 5 ) is emitted so as to be directed away from the bottom surface ( 12 ); and F) the markers ( 3 ) are arranged in a plane extending parallel to the top surface ( 11 ) and the laser beam ( 5 ) is emitted vertically relative to said plane.