Fig. 2From: The effect of different screw-rod design on the anti-rotational torque: a biomechanical comparison of three conventional screw-rod constructsIllustrations of the screw cap and groove characteristics. a The Legacy screw includes a “U” groove and a cap with a tip at the bottom; b The RF-F-10 screw has a “U” groove and a cap with a hole in the center; c The US II screw consists of an “L” groove and “U” capBack to article page