Normal pelvis. Coloured X-ray of the pelvis ofa 13-year-old girl. At top centre are the lumbarvertebrae of the spinal column, the lowest ofwhich articulates with the sacrum. The sacrumforms the back of the pelvis and is connected tothe large ear-shaped innominate bones. Eachinnominate bone is formed from three fused bonesand accommodates the articulation of the hipjoint: the ball of the head of each femur (lowerleft and right) can be seen fitted into the socketor acetabulum on each side of the pelvis. In theadult female the pelvis is wider and shallower.The darker regions within the pelvis are areas ofgas in the intestine.