Fig. 4
From: Anatomical relation between S1 sacroiliac screws’ entrance points and superior gluteal artery
The point As were connected to form a region (green borders in the pictures) named as the S1 sacroiliac screw’s safe entrance bony area (Safe Area for short). The relations of the Safe Area and various branches of superior gluteal artery outside of the pelvis were observed. In Fig. 4, the deep superior branch of superior gluteal artery just passes through the Safe Area. In contrast, the branches of superior gluteal artery and the Safe Area do not intersect in Fig. 5, “D” means the shortest distance between the bony Safe Area and the deep superior branch