Patent ID: 7636595

Claim:
A system to navigate an instrument relative to a portion of a patient's anatomy, comprising: an instrument including an engaging end, a working end, and a non-linear shaft extending between said engaging end and said working end; a member selectively engageable to said engaging end such that said member is operable to be engaged and disengaged from said engaging end; a first tracking sensor interconnected with said instrument at said working end of said shaft; and a tracking system configured to track said first tracking sensor; wherein said tracking system comprises a processor configured to determine an orientation of said member relative to said first tracking sensor when said member is engaged to said engaging end by: determining at least three points on a portion of said member; determining a plane of the first member based at least in part upon the determined three points; confirming the accuracy of the determined plane by: determining a fourth point on the portion of the first member that should be on the determined plane; and determining whether the fourth point is on the determined plane; wherein said engaging end defines a first axis that is non-coaxial with a second axis defined by said working end such that said first tracking sensor is connected to the working end of the shaft that is non-coaxial and non-linear with said engaging end.