| 摘要 |
It comprises at least one cylinder (1) of which one of the ends is closed by a bottom (2) while the other end comprises a ring (5) which allows connection to another cylinder (1), the median part of the cylinder (1) being pierced with a through hole (1a) for fitting a tubular sleeve (3) which is intended for forcible insertion of a sphere (4) which is integral with a pedical screw (8) and in that, between each sleeve (3) and the bottom (2), an elastic block (6) is placed while another block (7) is inserted between each sleeve (3) and the assembly ring (5). <IMAGE> |
