Dynamic reference arrays use markers and trackers to register a patients anatomy to computer system. Wherein the dynamic reference array may be screwed into a patients spinous process, clamped on to a spinous process, or attached to the spinous process using posts. In embodiments, a dynamic reference array may comprise a single structure comprising and attachment member and a scaffold. In alternate embodiments, the dynamic reference array may comprise distinct structures that allow the dynamic reference array to swivel and collapse in order to facilitate registration, while not interfering with a surgical procedure.
