Fig. 2.

Axial CT image in the delayed phase shows the right ureter (white arrow) curving into the greater sciatic foramen in the infrapiriformis region. The sciatic nerve (orange arrow) and inferior gluteal vessels (blue arrow) are also seen at this infra-piriformis level. There is slight protrusion of the small bowel (black arrow) into the greater sciatic foramen. The left ureter (red arrow) has a somewhat posterior course near the sciatic notch, but subsequently coursed anteriorly towards the bladder (color version of figure is available online).