A longitudinal support having a first and second longitudinal support element. The first longitudinal support element having a longitudinal axis, includes first and second coaxial connecting segments provided with a first end and a second end, and an deformable articulated socket on the second connecting segment first longitudinal support element. The deformable articulated socket is axially open and can be deformed transversely to the longitudinal axis. The articulated socket includes a hollow spherical segment-like cavity with a diameter of D with an opening on the second end that is concentric with the longitudinal axis and has a diameter of d, while d