1. A system for determining a position and a change in the position of an anatomical structure, comprising: a surgical navigation system; a substrate capable of being removably mounted to an outer surface of a body, wherein the body includes an anatomical structure; a sensor attached to the substrate that can be tracked by the surgical navigation system; a positional device attached to the substrate that determines a position of the anatomical structure; a first circuit for calculating a global position of the anatomical structure by correlating a position of the sensor and the position of the anatomical structure; and a second circuit for displaying the global position of the anatomical structure on a display unit.