A polyaxial bone screw assembly includes a threaded shank body having an integral upper portion receivable in a one piece receiver, the receiver having an upper channel for receiving a longitudinal connecting member and a lower cavity cooperating with a lower opening. A down-loadable compression insert and a friction fit split retainer are located in the receiver providing pop- or snap-on assembly of the shank with the receiver either prior to or after implantation of the shank into a vertebra. Laterally located, spaced crimping apertures in the receiver press receiver walls into engagement with the insert to prohibit rotation of the insert with respect to the receiver.
