Abstract: A pedicle screw assembly consists of a screw having a part spherical head providing a saddle shaped contact surface for a connecting rod, the head is held in a coupling member allowing limited angular movement between the screw and coupling member in one plane only and this plane is at right angles to the contact surface. Surfaces are provided in the connecting member for supporting a connecting rod, which is securable in the coupling member by a cap engaging in the coupling member to clamp the connecting rod against the supporting surfaces while still enabling the screw to move angularly with respect to the coupling member.