Lu Q, Zhou R, Gao S, et al. - This study was undertaken to explore the association between the infra-acetabular corridor diameter (IACD) and the minimum thickness of medial acetabular wall (MTMAW), and to clarify the way of screw placement. Researchers obtained computed tomography (CT) data of 100 normal adult pelvises (50 males and 50 females respectively) and pelvis three-dimensional (3D) reconstruction was conducted by using Mimics software and the 3D model was imported into Geomagic Studio software. They further examined the association between IACD and MTMAW. The results demonstrate that, by measuring the MTMAW in the CT axial layers, the placement mode of the infra-acetabular screw can be ascertained preoperatively. The in-out-in screw entry point was around 2 mm outwards and backwards, and closer to true pelvic rim in comparison with all-in screw.