Ilium facts for kids

The ilium is a big, flat bone that's part of your pelvis. You can feel the top of it when you put your hands on your hips! It's one of three main bones that make up each side of your hip bone, connecting your spine to your legs.

The human pelvis

What is the Ilium?

The ilium is the largest and uppermost part of the hip bone. It's shaped a bit like a fan or a wing. This bone is super important because it helps form your pelvis. The pelvis is like a strong, bony ring at the bottom of your body. It connects your upper body to your lower body.

Where is the Ilium Located?

The ilium is found on both sides of your body. It sits above the other two main pelvic bones: the ischium and the pubis. Together, these three bones fuse, or grow together, as you get older. This usually happens when you are around 15 to 17 years old. Before that, they are separate bones connected by cartilage.

The Pelvic Girdle

The ilium is a key part of the pelvic girdle. Think of the pelvic girdle as a strong base for your body. It supports your weight when you stand, walk, or run. It also protects important organs like your bladder and parts of your intestines.

What Does the Ilium Do?

The ilium has several important jobs in your body:

• Supporting Weight: It helps carry the weight of your upper body. This weight is then passed down to your legs.
• Muscle Attachment: Many strong muscles attach to the ilium. These muscles help you move your legs and trunk. They are important for walking, running, and jumping.
• Protecting Organs: The wide, flat part of the ilium acts like a shield. It helps protect the soft organs inside your lower belly.
• Bone Marrow: Inside the ilium, like other large bones, is bone marrow. This marrow is where your body makes new blood cells.

Iliac Crest

The top edge of the ilium is called the iliac crest. This is the part you feel when you put your hands on your hips. It's a thick, curved border. The iliac crest is a very important landmark for doctors. They often use it to find other parts of your body or to take bone marrow samples.

How Does the Ilium Connect?

The ilium connects to other bones in two main ways:

• Sacroiliac Joint: At the back, the ilium connects to the sacrum. The sacrum is a triangular bone at the base of your spine. This connection forms the sacroiliac joint. This joint is very strong and doesn't move much. It helps transfer weight from your spine to your legs.
• Hip Joint: At the side, the ilium helps form part of the acetabulum. The acetabulum is a deep socket. The head of your femur (thigh bone) fits into this socket. This creates your hip joint, which allows for a wide range of leg movements.

Ilium in Animals

The ilium is found in many animals, not just humans! It's a common bone in tetrapods. Tetrapods are animals with four limbs, like mammals, birds, reptiles, and amphibians. The shape and size of the ilium can vary a lot between different animals. This depends on how they move and what their bodies are designed for. For example, the ilium in a bird is very different from that in a human. This is because birds need a strong, lightweight pelvis for flight.

See also

In Spanish: Ilium (desambiguación) para niños