The invention relates to an implant for supporting a vertebral column, including at least one attachment element (300) and a connecting rod. Such an attachment element (300) includes an anchoring member (13) in a vertebral body, as well as a head (14) in which a passage opening (15) is provided that is conducive to receiving a connecting rod (12), the attachment element (300) being remarkable in that it comprises a means (316) for centering said rod, said rod-centering means being mounted on a spring-back means (317) placed in said head (14), said centering means (316) and said head (14) being movable relative to each other. A connecting rod (12) capable of being inserted into a passage opening (15) of an attachment element (300) includes at least one second centering surface (19). The attachment element (300) and the connecting rod (12) engage to form an implant in which said rod is rotatably and/or translatably movable relative to the anchoring member (13).
