A shank (12) has an upper shank portion (18) and a lower shank portion (20).

The screw rod driving device (3) comprises a handwheel (31), a screw rod (32), a screw rod seat (33) and a fixing block (34).

The bolt (40) includes a threaded shank (41).

A ball screw (26) has a screw shaft (29), a nut (25) surrounding the screw shaft (29), and balls (30) engageable with the screw shaft (29) and the nut (25).

A longitudinal threaded shaft (14) transverses the longitudinal hollow portion.

The pedicle screw includes a head portion and a threaded shaft.

A lead screw (5), a lead screw nut and a drive member are aligned with an axis (4).

The fastening element comprises a threaded shaft (7) comprising a magnetostrictive material.

One post (17) is provided with a threaded stud (18) extending axially from the bead, and the other post (21) is tapped within the bore of the bead (22) to receive the threaded stud.

The screw rod transmission apparatus (17) comprises a motor device (172) outputting a driving force, and a screw rod (173) driven by the motor device (172).

The rod receiver containing a receiver body coupled to a threaded shaft.

The screw connection comprises a projecting threaded pin (13,24) and a threaded hole (14,25) corresponding thereto.

The stop is formed by manufacturing a threaded rod having an unthreaded cylindrical portion and one or more grooves (5) cut or manufactured longitudinally in the rod across both the threaded section and the unthreaded portion.

Ideally, this connecting element is a chain or a screw spindle.

Boss (4) may be internally threaded or it can include an externally threaded spindle .