A vertebral rod assembly with first and second members that may rotate about a first axis. Each of the first and second members includes a base and a vertebral support rod extending from the base. An extension extends from the base on the first member into an opening formed in the base of the second member. A ring is sized to extend around the extension. A fastener engages with the ring to lock the first and second members, and to prevent relative rotation between the first member and second member.