18. An anchor assembly comprising: an anchor body having a longitudinal axis; an anchor head fixed to the anchor body; the anchor head including a U-shaped yoke; a shaft spanning the U-shaped-yoke; a saddle having a transverse bore and a longitudinal bore which intersects the transverse bore; the shaft being received through the transverse bore of the saddle such that a portion of the saddle extends around the shaft between the shaft and the anchor head such that the saddle is secured to the anchor head and can move relative to the anchor head; said saddle having a slot intersecting the longitudinal bore; a set that is received in said saddle and can be selectively advanced into the slot; said slot adapted to receive a rod whereby, with the rod received in the slot, advancement of the set into the slot forces the rod against the shaft thereby securing the rod to the saddle and locking the saddle relative to the anchor head.
18. An anchor assembly comprising: an anchor body having a longitudinal axis; an anchor head fixed to the anchor body; the anchor head including a U-shaped yoke; a shaft spanning the U-shaped-yoke; a saddle having a transverse bore and a longitudinal bore which intersects the transverse bore; the shaft being received through the transverse bore of the saddle such that a portion of the saddle extends around the shaft between the shaft and the anchor head such that the saddle is secured to the anchor head and can move relative to the anchor head; said saddle having a slot intersecting the longitudinal bore; a set that is received in said saddle and can be selectively advanced into the slot; said slot adapted to receive a rod whereby, with the rod received in the slot, advancement of the set into the slot forces the rod against the shaft thereby securing the rod to the saddle and locking the saddle relative to the anchor head. 19. The anchor assembly of claim 18 wherein the saddle can move with three degrees of freedom about said shaft prior to locking the saddle relative to the anchor head.