Vertebral column manipulation systems include spinal derotation instrumentation to affect one or more derotation maneuvers on a scoliotic spine or on a spine having one or more displaced, misaligned or curved vertebral levels. Derotation instrumentation is attached to at least one vertebral body, with the instrumentation including at least two elongated extensions mounted to and extending proximally from the at least one vertebral body. A linking assembly extends between and links proximal ends of the extensions to one another. The linking assembly includes first and second mounting assemblies movably engaged to an elongate link member extending transversely to the extensions. Each of the mounting assemblies includes a movable joint for receiving the proximal end of a respective one of the extensions and a cam assembly for securing the mounting assembly in position relative to the link member and to fix the joint around the extension.