Abstract: A modular tulip assembly has a rod receiving tulip and a saddle. The saddle is interlockingly held inside a distal portion of the tulip. The saddle has an external locking groove or recess. The tulip has a locking projection. The locking projection is positioned into the external locking groove or recess and holds the saddle in a pre-loaded unlocked state ready to be pushed onto a head of an implanted bone screw. Upon receiving the head of the bone screw, the saddle can be moved distally relative to the tulip to a locked state by moving the locking groove or recess distally past the locking projection to where the proximal end of the saddle is past abutting the locking projection.