Abstract: The kit of parts comprises a distal shaft part (2) and a neck part (3) which can be equipped with a joint ball (10), with the neck part being supported on the shaft part (2) by approximately rectangular shaped supporting surfaces (2c) and (3c) positioned transverse to the longitudinal axis (L) of the shaft part (2). The shaft part (2) and the neck part (3) are provided with prismatic guide surfaces (2d) and (3d) brought together in a form-fit and orientated parallel to the longitudinal axis (L), and are rigidly connected to each other by an extensible shaft screw (11) which can be elastically prestressed to carry a predetermined bending moment. The guide surfaces (2d) and (3d) are formed at a spigot extension (2b) of the shaft part (2) and at a complementary recess (3b) of the neck part (3), respectively.

Abstract: A connection member for the connection of a resilient rod with a bone screw that can be anchored in a vertebra. The connection member comprises a fastener that acts on the rod, an accommodation part and a connection part. The accommodation part has a first opening for the accommodation of the rod. The first opening has a substantially round inner boundary surface formed from several 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 least three distinct and non-contiguous points.