A fan on your chest
The pectoralis major spreads out from your breastbone and collarbone like an open fan.
Then all its fibers come together to a point on your upper arm bone, near your shoulder.
Pectoral comes from the Latin word for chest, and major means bigger. So it's the 'bigger chest muscle.'
Push, hug, throw
Try it: put your right hand flat on the left side of your chest. Now push your left hand hard against a wall. Feel the muscle get firm?
Your chest muscles pull your arms in toward the middle. That's what happens in a big hug.
They also help swing your arm forward when you throw a ball, push a swing or swim.
The smaller helper
Under each big chest muscle is a smaller one called the pectoralis minor. Minor means smaller.
It helps move your shoulder blade forward and down. When you take a really huge breath, it can help lift your ribs too.
Push-ups, the fun way
Push-ups use your chest muscles, your shoulders and the triceps on the backs of your arms. Your belly helps keep you straight like a plank.
Start with wall push-ups. Stand facing a wall, put your hands flat on it, bend your elbows to bring your nose close, then push back.
Challenge a grown-up to a wall push-up contest!