hipbone

The hipbone, also called the os coxae, is a large bone that forms one side of the pelvis. In a child, it starts as three separate bones: the ilium, the ischium, and the pubis. As the body grows, these bones join together, so in an adult they look like one solid bone. This joined bone helps shape the pelvic cavity and gives the body a strong frame in the lower trunk.

Its job is both supportive and protective. The hipbone helps carry the weight of the upper body and pass it down to the legs. On its outer side is the acetabulum, a deep socket where the head of the femur fits to form the hip joint. Because of this joint, the body can walk, sit, turn, and keep balance. The bone also protects organs in the pelvic area and provides firm attachment points for many muscles of the abdomen, hips, and legs.

In everyday use, the word may refer to the bony part you can feel at the side of your body, especially the upper rim of the pelvis. In medical talk, it can mean the whole bone on either side of the pelvis. People sometimes confuse it with the hip joint or with the upper femur, which is why phrases like "broken hip" do not always mean the hipbone itself is broken. Overall, it is one of the main bones that gives the lower body strength, shape, and movement.