The quick answer
Bones give your body its shape and hold you up. They protect soft parts inside you, like your brain, heart and lungs. Together with your muscles, they help you move.
RankiTanki, what if I had no bones at all? Could I squeeze under a door like an octopus?
TankiOctopuses really can do that! But without bones you would just flop on the floor. Let’s see why bones matter so much.
Your body’s frame
All the bones in your body together are called your . It works like the poles of a tent. Without the poles, a tent falls flat. Without your skeleton, you could not sit, stand or walk.
A grown-up has 206 bones. Babies are born with around 300. Many of a baby’s bones are soft at first. As the baby grows, some of them slowly join together into bigger bones. That is why grown-ups end up with fewer.
Bones keep you safe
Some bones work like a helmet or a shield. They protect the soft, important parts inside you.
- Your is a hard case around your brain.
- Your ribs make a cage that guards your heart and lungs.
- Your , or backbone, is a stack of small bones. It protects a bundle of that carries messages to and from your brain.
Bones and muscles are a team
Bones cannot move on their own. They need muscles. Your muscles are joined to your bones. When a muscle pulls, the bone moves.
The places where two bones meet are called . Your knees, elbows, shoulders and fingers all have joints. Some joints bend like the hinge of a door. Your shoulder can swing round in a circle, like a ball turning in a cup.
RankiSo when I wiggle my fingers, muscles are pulling on lots of tiny bones?
TankiYes. Your hands are packed with little bones. That’s a lot of teamwork just to wave hello.
Bones are alive
Bones in a museum look like dry sticks. But the bones inside you are alive. Blood flows through them, and they grow as you grow. If a bone breaks, a doctor helps to keep it still, and the bone slowly mends itself.
Inside some bones is a soft, jelly-like part called . It makes new blood cells for your body every day.
The smallest bone in your body is deep inside your ear. It is called the stirrup, and it is about the size of a grain of rice. The longest bone is in your thigh, the top part of your leg. It is called the .
Running, jumping and playing all help your bones grow strong. So does eating well.
Try it
Go on a bone hunt
You need
What to do
- Press gently on the front of your knee. Can you feel your kneecap move?
- Run your fingers along your side and count some of your ribs.
- Bend your fingers and feel the bumps of your knuckles.
- Count the bones you can feel in one finger. Is your thumb different?
- Draw the bones you found on your paper.
RankiBones hold me up, keep my brain safe and even make blood. Okay, I’ll keep my skeleton.
TankiGood choice. Now go and thank it with a big jump!
Big words
- skeleton
- All the bones in your body together.
- skull
- The bones of your head that protect your brain.
- spine
- Your backbone, a stack of small bones down your back.
- nerves
- Thin threads that carry messages between your brain and body.
- joints
- Places where two bones meet, so you can bend and move.
- marrow
- The soft middle of some bones that makes new blood cells.
- femur
- Your thigh bone, the longest bone in your body.
Quick quiz
1. How many bones does a grown-up have?
A grown-up skeleton has 206 bones.
2. Which bones protect your heart and lungs?
Your ribs make a strong cage around your heart and lungs.
3. Where is the smallest bone in your body?
The stirrup, deep inside your ear, is the smallest bone of all.
For parents and teachers
The adult skeleton has 206 bones, while babies have more, many of them partly cartilage, which fuse during childhood. Bones grow in length at growth plates near their ends, which is why children keep getting taller into their teens. Linking bones to play and movement is a positive way to bring this topic into everyday life.
Pictures marked “AI generated” were made with AI tools. Ranki and Tanki are AI generated characters. Found a mistake? Write to info@pr-geo.com and we will fix it.
