A medical device and methods of use thereof are provided for supporting a structure (e.g., bone). A screw assembly is provided that is comprised of a base, an arm, and an interconnection means for coupling the base to the arm. The interconnection means allows the arm to be positionable in a first position that is parallel to a long axis of the base and positionable in a second position that is perpendicular to the long axis of the base. The base is configured for attachment to a structure and the arm configured for attachment to a support structure. A support structure is provided that includes one or more receivers having locking means, which can be configured as an open-ended saddle for attachment to a medical device (e.g., a screw assembly). The support structure is configured to receive one or more medical devices and lock the medical devices to the support structure after installation in a patient.