Abstract: An instrument for manipulating a bone anchor and, in turn, a vertebral body to which the bone anchor is attached. The exemplary instrument includes an inner shaft, an anchor engagement mechanism, and an outer sleeve disposed about the inner shaft. The exemplary instrument may be employed to manipulate a bone anchor for implantation or adjustment. The exemplary instrument may also be use engage a bone anchor implanted in a vertebra and maneuver the bone anchor and the vertebra by manipulating the instrument. For example, the exemplary instrument may be employed to rotate the bone anchor and the vertebra relative to other vertebrae and thereby by correct the angular orientation of the vertebra. The instrument, when employed in the exemplary manner, thus may be used to effect segmental correction of the angular orientation of the vertebrae of the spine.