Abstract: A push-pull prop includes inner and outer tubes reversibly fixed to each other, a threaded bar screwed into a threaded portion of a first end of the inner tube, a fixing head including a coupling portion fixable to a first end of the outer tube and a locking portion rotationally connected to the coupling portion, so the outer tube can rotate with respect to the locking portion about a rotation axis to thread the inner tube on the threaded bar. The locking portion is rotationally connected to a first connecting element at a first surface so the prop can rotate about a first tilting axis perpendicular to the rotation axis. The threaded bar is rotationally connected to a second connecting element at a second surface, so the prop can rotate about a second tilting axis perpendicular to the rotation axis and parallel to the first tilting axis.