1. A position monitoring system for a surgical procedure comprising: a single vectorized fiducial reference adapted to be fixed to a surgical site of a surgical patient; an imaging sensor adapted to be disposed proximate the surgical site and adapted to provide live image data of the surgical site; an illuminator adapted for illuminating the surgical site with radiation; a first vectorized tracking marker rigidly attached in a predetermined fixed three-dimensional position and orientation relative to the single fiducial reference; a second vectorized tracking marker rigidly attached in a predetermined fixed three-dimensional position and orientation relative to the imaging sensor; a tracker configured and disposed for obtaining image information of at least the first and second tracking markers; a controller coupled to the tracker and to the imaging sensor and comprising a processor with memory, the memory storing scan data and a software program, the scan data representative of the surgical site before the surgical procedure with the single fiducial reference fixed to the surgical site and the software program having a series of instructions which when executed by the processor determines from the image information current positions and orientations of the first and second tracking markers, and relates the scan data to the current three-dimensional position and orientation of the single fiducial reference and to the current live image data of the surgical site; and a display system coupled to the controller and adapted to show during the surgical procedure the current live image of the surgical site in three-dimensional spatial relationship relative to the scan data.