iliac fossa iliac fossa the iliac fossa is a large, smooth, concave surface on the internal surface of the ilium (part of the three fused bones making the hip bone). iliac fossaright hip bone. internal surface. (iliac fossa visible at upper left.)pelvic girdle. (region of iliac fossa visible at tip of arrow pointing from the word "ilium".)detailsidentifierslatinfossa iliacata98a02.5.01.115ta21331fma75316anatomical terms of bone structure the iliac fossa is bounded above by the iliac crest, and below by the arcuate line. it is bordered in front and behind by the anterior and posterior borders of the ilium. the iliac fossa gives origin to the iliacus muscle. the obturator nerve passes around the iliac fossa. it is perforated at its inner part by a nutrient canal. below it there is a smooth, rounded border, the arcuate line, which runs anterior, inferior, and medial. when the "left" or "right" adjective is used (e.g "right iliac fossa"), the iliac fossa usually means one of the inguinal regions of the nine regions of the abdomen. additional images the iliacus and nearby muscles iliac fossa iliac fossa hip joint. lateral view. iliac fossa. lumbar and sacral plexus. deep dissection. anterior view