Fig. 2

Standardized design of S2AI screw trajectory and measurement of relevant parameters. a Transverse image of screw placement plane. The blue line represents the axis of the nail track, and the yellow line represents the distance between the anterior cortex of the ilium and the axis of the screw trajectory by 5 mm. b Sagittal image of screw placement plane. The blue line indicates the point of insertion to the inferior margin of anterior inferior iliac spine. c Transverse image of screw placement plane. Alpha is the lateral angle of the screw trajectory, the blue line represents the length of the screw trajectory, and the red line represents the width of the ilium. d Sagittal image of screw placement plane. Beta is the caudal angle of the screw trajectory, the yellow line represents the distance from the screw trajectory to the ischial notch, the green line represents the distance from the screw trajectory to the upper iliac cortex, and the red line represents the distance from the screw trajectory to the acetabulum