The Body

Grown-ups

Tiniest bones

Ossicles, said OSS-ih-kulz

Deep inside each ear are three tiny bones that wiggle to help you hear.

Sound comes in the tunnel, shakes the eardrum and three tiny bones, and the snail sends the message to your brain. Tap any part!

Hammer, anvil and stirrup

Behind your eardrum is a tiny room called the middle ear. Inside it are the three smallest bones in your body.

They are named for their shapes. The hammer looks like a little hammer. The anvil looks like the heavy metal block a blacksmith bangs on. The stirrup looks like the loop a rider puts a foot in on a horse's saddle.

Their science names are malleus, incus and stapes. Malleus means hammer. Incus means anvil. Stapes means stirrup.

The smallest bone of all

The stirrup is the smallest bone in your whole body. It's only about 3 millimeters long. That's smaller than a grain of rice!

All three ear bones together could sit on the tip of your finger.

Here's a strange thing: your ear bones are already about their grown-up size when you are born. Most of your other bones keep growing for years.

How they help you hear

Sound is the air shaking. When a sound reaches your ear, it makes your eardrum shake, a bit like the skin of a drum.

The hammer is joined to the eardrum, so it shakes too. It passes the shake to the anvil, and the anvil passes it to the stirrup. It's like a tiny relay race.

The stirrup pushes on a little window into your inner ear, which is full of liquid. The bones make the shake stronger, so it can move the liquid. Then tiny hairs in there send a message to your brain. You hear!

Try it: hum with your mouth closed. Then put your fingers in your ears and keep humming. The hum gets louder, because the sound is traveling through the bones of your head.

A tiny muscle helper

Your stirrup has a helper: the smallest muscle in your body. It holds on to the stirrup.

When a sound is very loud, this muscle tightens and holds the stirrup back a little. That helps protect your inner ear.

It can't block every loud noise, though. So it's smart to cover your ears or wear ear protection near very loud sounds.

🤩 Wow facts

  • The stirrup in your ear is the smallest bone in your body, smaller than a grain of rice.
  • Your ear bones are about their grown-up size on the day you are born.
  • The three ear bones are called the hammer, the anvil and the stirrup because of their shapes.
  • The smallest muscle in your body holds on to the smallest bone.
  • Myth: You hear with the outside part of your ear. Truth: That part just catches sound. The hearing happens deep inside, with help from these tiny bones.

💚 Look after it

  • Keep sounds at a comfy level. If you have to shout to be heard, it's too loud to stay in for long.
  • Wear earmuffs or earplugs at very loud places, like fireworks shows or car races.
  • Keep headphones at a medium volume, and take breaks.
  • Never put cotton swabs or small things inside your ears. A grown-up can clean the outside part.

🩹 When something goes wrong

When liquid gets in the way. Sometimes, during a cold, liquid collects behind the eardrum. Then the tiny bones can't wiggle as well, so sounds seem quiet or muffled, and the ear may hurt. Tell a grown-up. A doctor can look in your ear and help it get better.

🙋 Questions kids ask

Why are my ear bones so tiny?

Sound shakes are tiny, so the bones that pass them on need to be tiny and light too. Big, heavy bones would be too slow to wiggle.

Can I touch my ear bones?

No. They are deep inside your skull, behind your eardrum. You can't feel them, but they work every time you hear.

Why does my voice sound strange in a recording?

When you talk, you hear your voice through the air and also through the bones of your head. A recording only catches the air part, so it sounds different to you.

🧠 Quick quiz

Question 1 of 3Which is the smallest bone in your body?

🔗 It works with

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