The Pelvis
The pelvis is a symmetric ring of bones at the base of the spine and joined to the sacrum, that protects abdominal organs such as the bladder, rectum and, in women, the uterus. It also provides support for the rest of the body above it. Each side of the pelvis is made up of three fused bones: the ilium (the wide bone at the top), the ischium, and the pubis. Both parts of the pubis bone are joined to the sacrum at the rear; in women these bones can spread apart to allow more room for a baby to be born. The three bones, collectively called the hip bone, come together to form a cup-like depression that creates the socket half of the ball-and-socket joint with the femur. Muscles that are attached to the pelvis include the abdominal wall, the buttocks, the lower back, and the thighs. There are differences between the male and the female pelvis, mostly because of the role the female pelvis plays in childbirth. The male pelvis is larger, but smaller inside, with a narrow pubic arch. The female pelvis is wider, especially the space between each half, and the pubic arch is also wider.  |