The study offered a detailed anatomical background of the blood supply of the innominate bone. The acetabulum was richly supplied from the superior gluteal, inferior gluteal, obturator and iliolumbar arteries. The osteolytic lesions were arranged according to the distribution of the osseous foramina. The trabeculae of the innominate bone were arranged into two sets: one in the anterior ilium and the other in the posterior ilium. They meet in the region above the superior margin of the acetabulum. The trabeculae were arranged in lamellar bony cylinders and in areas which faced minor forces they showed a meshwork arrangement. The bone differs in facing the forces subjected on it from one region to another. In the posterior acetabulum it depends on the trabecular bone volume and thickness. In the posterior ilium it depends on the arrangement of its trabeculae.