Three components are proposed, each having at its core a system for producing measurements of the relative motion of anatomical structures of mammals (the "measurement system"). The measurement system in this case would be comprised of an apparatus for imaging the joint of through a prescribed motion, and a process and mechanism for deriving quantitative measurement output data from the resulting images. The components of the present invention include: (1) a software device for reporting measurement output of the measurement system and for allowing users to interact with the measurement output data； (2) an apparatus and method for utilizing measurement output of the measurement system for therapeutic and surgical applications such as surgical navigation and patient positioning during a therapeutic procedure； and (3) an apparatus providing input image data for the measurement system that assists with the imaging of joints connecting anatomical regions that are in motion during operation.
