to the teeth in the spinal rod receiving bore of the pivot base these u clamp teeth 44 and 46 grip transverse connector rod 19 when the clamp is tightened once the orientation of the clamp on the pivot base has been established and deemed acceptable by the surgeon it is essential that the orientation remain constant for that purpose there are four ribs 47 on the u clamp two of these spaced diametrically apart face downward from the top of the clamp and two of them face upward from the bottom of the clamp these ribs or ridges seat in the grooves in the upper and lower faces 27 and 28 respectively of the pivot base the grooves are in a sunburst array around the axis 29 of the pin receiving aperture in the pivot base the ability to interfit the ridges 47 of u clamp 22 in the grooves in the top and bottom surfaces of the pivot base enables locking these two parts in any of many possible rotational index positions chosen by the surgeon the pivot assembly 18 on the spinal rod 12 is exactly the same as assembly 17 just described on spinal rod 13 the orientation is different as shown in fig1 with the transverse connector rod 19 spanning the gap between the two u clamps on the respective pivot assemblies it is a feature of this invention that there is great freedom of discretion in the location and orientation of the pivot assemblies and the transverse connector the assembly allows for the necessary degrees of tilt rotation and angulation in three planes to make connections possible regardless of what the anatomy instrumented or deformity treated might be it allows for dynamic diagonal transverse connections with both.