In a woman, the pelvis is more delicate and the iliac crests are farther apart. These differences reflect the woman's role in pregnancy and delivery of children. When a child is born, it must pass through its mother's pelvis. If the opening is too small, a cesarean section may be necessary. The picture above is of a female pelvis.
All divisions are approximations only.
W.B. Saunders Company. Van De Graaff, Kent M. Human Anatomy 5th Edition.