A medical navigation system, comprising: a processor adapted to be connected to a display; an electromagnetic sensor tracking system connected to the processor, wherein the electromagnetic sensor tracking system has an electromagnetic tracking coordinate system, wherein the electromagnetic sensor tracking system is adapted to measure the position of a sensor located in the electromagnetic tracking coordinate system; wherein the processor is adapted to: measure a position of the electromagnetic sensor tracking system; calculate an electromagnetic coordinate system to a table coordinate system transformation matrix based on the measured position of the electromagnetic sensor tracking system, wherein the table coordinate system is the coordinate system of a table adapted to support a patient during a medical procedure; receive a position of the sensor in the electromagnetic tracking coordinate system from the electromagnetic sensor tracking system; transform the position of the sensor from the electromagnetic tracking coordinate system to the table coordinate system using the electromagnetic coordinate system to table coordinate system transformation matrix; and deliver a signal to the display to render on the display a depiction of a position of a motion box based upon the transformed position of the sensor, wherein the motion box represents a three-dimensional space depicting a boundary of the motion box, wherein the electromagnetic sensor tracking system is adapted to generate a magnetic field within the motion box, wherein the processor is adapted to evaluate whether the sensor is within, at the boundary of, or outside of the motion box by measuring the position and orientation of the sensor in relation to the boundaries of the motion box, and wherein the rendered position of the motion box is registered to the table coordinate system. a processor adapted to be connected to a display; an electromagnetic sensor tracking system connected to the processor, wherein the electromagnetic sensor tracking system has an electromagnetic tracking coordinate system, wherein the electromagnetic sensor tracking system is adapted to measure the position of a sensor located in the electromagnetic tracking coordinate system; wherein the processor is adapted to: measure a position of the electromagnetic sensor tracking system; calculate an electromagnetic coordinate system to a table coordinate system transformation matrix based on the measured position of the electromagnetic sensor tracking system, wherein the table coordinate system is the coordinate system of a table adapted to support a patient during a medical procedure; receive a position of the sensor in the electromagnetic tracking coordinate system from the electromagnetic sensor tracking system; transform the position of the sensor from the electromagnetic tracking coordinate system to the table coordinate system using the electromagnetic coordinate system to table coordinate system transformation matrix; and deliver a signal to the display to render on the display a depiction of a position of a motion box based upon the transformed position of the sensor, wherein the motion box represents a three-dimensional space depicting a boundary of the motion box, wherein the electromagnetic sensor tracking system is adapted to generate a magnetic field within the motion box, wherein the processor is adapted to evaluate whether the sensor is within, at the boundary of, or outside of the motion box by measuring the position and orientation of the sensor in relation to the boundaries of the motion box, and wherein the rendered position of the motion box is registered to the table coordinate system. measure a position of the electromagnetic sensor tracking system; calculate an electromagnetic coordinate system to a table coordinate system transformation matrix based on the measured position of the electromagnetic sensor tracking system, wherein the table coordinate system is the coordinate system of a table adapted to support a patient during a medical procedure; receive a position of the sensor in the electromagnetic tracking coordinate system from the electromagnetic sensor tracking system; transform the position of the sensor from the electromagnetic tracking coordinate system to the table coordinate system using the electromagnetic coordinate system to table coordinate system transformation matrix; and deliver a signal to the display to render on the display a depiction of a position of a motion box based upon the transformed position of the sensor, wherein the motion box represents a three-dimensional space depicting a boundary of the motion box, wherein the electromagnetic sensor tracking system is adapted to generate a magnetic field within the motion box, wherein the processor is adapted to evaluate whether the sensor is within, at the boundary of, or outside of the motion box by measuring the position and orientation of the sensor in relation to the boundaries of the motion box, and wherein the rendered position of the motion box is registered to the table coordinate system.