US Patent 8951290 Multi-axial connection system

A system and method for a multi-axial connection of an apparatus to bone. The system may include a fastener inserted into a body and a head of the fastener held within a chamber of the body through a combination of a retention ring, a pressure cap, a rod, and a compression element. The compression element applies force to the rod which, in turn, pushed on the pressure cap. The force on the pressure cap urges it against the head of the fastener and pushed it against the retention ring. The force on the retention ring causes it to expand to the walls of the chamber. Once the ring can no longer expand within the chamber, the head of the fastener is wedged between the retention ring and the pressure cap.