The Body

Grown-ups

Forearm muscles

The muscles that wiggle your fingers live in your arm and pull long strings to your fingers.

Muscles can only pull. The biceps on top bends your elbow and the triceps underneath straightens it. Press Flex, or tap any part!

No muscles in your fingers

Here's a surprise: your fingers have no muscles inside them. They have bones, tendons, nerves and blood vessels, but no muscles.

So what moves them? Strong muscles in your forearm, the part of your arm between your elbow and your wrist.

These muscles pull on long cords called tendons. The tendons run through your wrist and into your fingers, like the strings on a puppet.

Watch it happen

Try it: rest your arm on a table with your palm up. Wiggle your fingers fast and watch the inside of your forearm. See little ripples under the skin?

Now make a tight fist. Feel your forearm get hard with your other hand.

Then turn your hand over and wiggle your fingers again. Watch the back of your hand: you can see the tendons sliding.

Front and back

The muscles on the palm side of your forearm bend your wrist and curl your fingers. That's how you grip things.

The muscles on the back side straighten your fingers and bend your wrist back. Partners again!

Small muscles in your palm help with careful moves, like spreading your fingers wide or touching your thumb to your pinky. The soft, fat pad at the base of your thumb is made of thumb muscles.

Grip power

Your forearm muscles help you hang on the monkey bars, hold a pencil, open a jar and turn a doorknob.

Writing or drawing for a long time can make them tired. Shake out your hands and wiggle your fingers to give them a break.

Try it: put your hand flat on a table and fold your middle finger under. Now try to lift your ring finger. Tricky, right? Its tendons are linked to the fingers next to it.

🤩 Wow facts

  • Your fingers have no muscles inside them. Muscles in your forearm move them with long tendons.
  • Forearm muscles pull on tendons a bit like a puppeteer pulls on strings.
  • You have about 20 muscles in each forearm.
  • Small muscles in your palm help with careful moves, like touching your thumb to your pinky.
  • The soft pad at the base of your thumb is made of thumb muscles.
  • It's hard to lift your ring finger all alone, because its tendons are linked to its neighbors.

💚 Look after it

  • Shake out and stretch your hands when you write or draw for a long time.
  • Play with clay or squeeze a soft ball to keep your grip strong.
  • Take breaks from game controllers and screens to rest your hands.

🩹 When something goes wrong

Tired hands. Lots of writing or gaming can make your hand and forearm ache. Take a break and wiggle your fingers. If it keeps hurting or tingles, tell a grown-up.

🙋 Questions kids ask

If there are no muscles in my fingers, how do they move?

Muscles in your forearm and palm pull on tendons that run into your fingers, like strings on a puppet.

Why can't I lift my ring finger by itself?

Its tendons are linked to the fingers beside it, so they like to move together.

🧠 Quick quiz

Question 1 of 2How many muscles are inside your fingers?

🔗 It works with

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