11. A dynamic spine stabilization component wherein the dynamic spine stabilization component comprises: a tubular shield having a lumen; the lumen having a proximal end and a distal end; the tubular shield being configured and adapted to be secured within a bore in a housing at a proximal end of a bone screw such that the lumen of the tubular shield is aligned with a longitudinal axis of the bone screw; a deflectable post having a proximal end, an elongated body and a distal end; the proximal end of said deflectable post extending from the proximal end of said lumen; a spherical retainer at the distal end of the deflectable post; the spherical retainer being pivotally associated with the distal end of the lumen; a spring positioned within the lumen between the deflectable post and the tubular shield such the spring flexibly resists pivoting of the deflectable post towards the tubular shield; a fastener adapted to secure the tubular shield within the bore in the housing of the bone screw; and whereby, with the tubular shield secured within the bore in the housing of a bone screw the spring flexibly aligns the deflectable post with the longitudinal axis of the bone screw.
11. A dynamic spine stabilization component wherein the dynamic spine stabilization component comprises: a tubular shield having a lumen; the lumen having a proximal end and a distal end; the tubular shield being configured and adapted to be secured within a bore in a housing at a proximal end of a bone screw such that the lumen of the tubular shield is aligned with a longitudinal axis of the bone screw; a deflectable post having a proximal end, an elongated body and a distal end; the proximal end of said deflectable post extending from the proximal end of said lumen; a spherical retainer at the distal end of the deflectable post; the spherical retainer being pivotally associated with the distal end of the lumen; a spring positioned within the lumen between the deflectable post and the tubular shield such the spring flexibly resists pivoting of the deflectable post towards the tubular shield; a fastener adapted to secure the tubular shield within the bore in the housing of the bone screw; and whereby, with the tubular shield secured within the bore in the housing of a bone screw the spring flexibly aligns the deflectable post with the longitudinal axis of the bone screw. 13. The dynamic spine stabilization component of claim 11 , wherein: the tubular shield has a limit surface positioned to contact the deflectable post after a first angle of pivoting of the deflectable post away from alignment with the tubular shield; and wherein deflection of the proximal end of the deflectable post after contact between the deflectable post and the limit surface requires at least double the load per unit of deflection than deflection of said proximal end prior to contact between the deflectable post and the limit surface.