1. A system for determining a position and a change in the position of an anatomical structure, comprising: a surgical navigation system; a substrate including means for removably attaching the substrate 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 to determine a position of the sensor; a magnetic transmitter attached to the substrate; a magnetic sensor comprising means for attachment to the anatomical structure, wherein the magnetic transmitter and the magnetic sensor are utilized to determine a position of the anatomical structure relative to the sensor; a first circuit for calculating a global position of the anatomical structure by concatenating the position of the sensor and the position of the anatomical structure relative to the sensor; and a second circuit for displaying the global position of the anatomical structure on a display unit.