We're born with 300 bones, but by the time we become adults some have fused together to leave us with exactly 206.
Bones are like human scaffolding - they help to keep us upright - but they also do loads of other things:
- Bones keep our vital organs, such as the brain, heart and lungs, safe from injury.
- They fit together, with the help of joints, so that we can move freely. Joints like your finger work as a lever, while others, such as your hip, are ball and socket joints.
- In moving joints, the ends of bones are covered by a tough slippery material known as cartilage, which stops the bones rubbing together.
- Bones contain soft tissue known as bone marrow, which makes our blood cells.
- Bones also store calcium.
