The Diaphragm

breathing · muscles · body systems

A muscle you use constantly. Your diaphragm is a sheet of muscle that stretches across the bottom of your rib cage. It works harder than any other muscle in your body because you breathe thousands of times every single day, whether you're awake or asleep.

How breathing works. When your diaphragm contracts and moves downward, it makes more room inside your chest. This creates space for your lungs to expand and fill with air. When it relaxes and moves back up, it pushes the air out.

Super hungry for energy. Your diaphragm has more mitochondria and blood vessels than any other skeletal muscle in your body. All these energy factories help it keep working without ever getting tired.

Separates two spaces. The diaphragm divides your body into two main chambers. Above it are your heart and lungs in the thoracic cavity, and below it is your stomach and other organs in the abdominal cavity.

Found in all mammals. Every mammal, from mice to whales, has a diaphragm. It's one of the special things that helped mammals become so successful and spread across the planet.