The pelvis or hip bone is a large bone that joins the vertebrae to the femur (thigh bone). It is one of the few bones where there are distinct if small differences between the male and female skeleton (a female's pelvis is slightly wider for the size of the skeleton).
The pelvis is very strong, but is very susceptible to diseases which decrease bone mass, such as osteoporosis. Moreover, when it is broken, it is very slow to heal as most of the body's weight is transferred through it and breaks tend to be large and easily infected. Complications from a broken pelvis is a common cause of death in the elderly.