Connection member for the connection of a resilient rod with a bone screw which can be anchored in a vertebra

A device for the connection of at least two vertebrae comprising at least two connection members;

• bone screws for the anchoring of the at least two connection members in the vertebrae;
• and at least one rod for connecting the at least two connecting members;
• wherein each of the at least two connecting members comprises fastener means that act on the rod, an accommodation part and a connection part, the accommodation part having a first opening for the accommodation of the rod;
• wherein the first opening has a substantially round inner boundary surface formed from several curved partial surfaces with at least three different radii of curvature such that upon connection of the connection member with the resilient rod, the connection member has at least three regions of contact with the resilient rod at at least three distinct and non-contiguous spaced locations.