Harvesting bone graft from the back of the waistline (posterior iliac crest) or front of the waistline (anterior iliac crest) to help create new bone growth in another area of the body. The posterior iliac crest bone graft is frequently obtained through an incision over the back of the waistline. Strips of dense cortical bone and less dense cancellous bone are removed from the outer portion of the iliac crest. The anterior iliac crest bone graft is obtained through a skin incision in the front of the waistline.