The Body

Grown-ups

Chewing muscle

Masseter, said muh-SEE-ter

Your chewing muscle is a strong squeezer on the side of your face that closes your jaw to bite.

Little muscles under your skin pull it into smiles and surprised faces, and strong ones on your jaw chew. Try the buttons, or tap a muscle!

Find your chewing muscle

Put your fingertips on your cheeks, in front of your ears and down near the corners of your jaw.

Now bite down hard. Feel a bump pop up under your fingers? That's your masseter squeezing. Relax your jaw, and it goes soft again.

It runs from your cheekbone down to the back corner of your lower jaw. You have one on each side.

Mighty for its size

The masseter is short and thick, and it can press your teeth together really hard. That's why it's often called one of the strongest muscles for its size.

Which muscle is the strongest of all? That depends on how you measure, so scientists don't pick just one.

Your back teeth can bite harder than your front teeth. That's why you crunch a carrot with your back teeth.

A chewing team

The masseter has helpers. The temporalis (tem-por-AL-is) is a fan-shaped muscle on the side of your head.

Try it: put your fingertips on your temples, the flat spots beside your eyes, and chew. Feel something move? That's your temporalis.

Two more muscles deep inside, called pterygoids (TER-ih-goyds), slide your jaw side to side and forward. That lets you grind your food into small, soft pieces.

Clenching and grinding

Some people squeeze their teeth together when they're concentrating or worried. Some grind their teeth while they sleep.

That can make the jaw muscles tired or sore. If your jaw feels sore in the morning, tell a grown-up. A dentist can help.

Try it: let your lips touch, keep your teeth a little apart and let your tongue rest. That's a relaxed jaw.

🤩 Wow facts

  • Masseter comes from a Greek word that means 'to chew.'
  • The masseter is often called one of the strongest muscles in your body for its size.
  • You have four main chewing muscles on each side of your head, and they work as a team.
  • Your back teeth can bite harder than your front teeth.
  • Your lower jaw is the only bone in your skull that moves, and your chewing muscles move it.
  • Chewing well turns food into small, soft pieces that are easier to swallow.

💚 Look after it

  • Take small bites and chew slowly.
  • Wear a mouthguard for sports like football, hockey or karate.
  • If you catch yourself clenching your teeth, relax: lips together, teeth apart.
  • Brush and floss so your teeth stay strong for all that chewing.

🩹 When something goes wrong

A sore jaw. Chewing lots of gum or clenching your teeth can make your jaw muscles tired and sore. Give them a rest. If your jaw clicks, hurts or is hard to open, tell a grown-up, who may take you to a dentist or doctor.

🙋 Questions kids ask

Why does my jaw get tired from chewing gum?

Gum keeps your masseter working and working. Like any muscle, it gets tired and needs a rest.

Why do I use my back teeth for hard food?

Your back teeth are wide and flat for crushing, and they can bite harder than your front teeth.

Can I feel my chewing muscle?

Yes! Put your fingers on your cheeks near your ears and bite down. Feel the bump? That's it.

🧠 Quick quiz

Question 1 of 2What does the masseter do?

🔗 It works with

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