Thoracic diaphragm

The Thoracic Diaphragm

The thoracic diaphragm, or simply the diaphragm, is a big, flat muscle at the bottom of the chest in humans and many animals. It helps us breathe. When the diaphragm tightens, it makes more space in the chest, and this pulls air into our lungs.

This special muscle separates the chest, where the heart and lungs are, from the area below, called the belly. The diaphragm is very busy and uses a lot of energy. Inside it, there are many tiny parts called mitochondria and lots of tiny blood vessels called capillaries—more than any other muscle.

Long ago, a person named Gerard of Cremona gave the diaphragm its name. In humans, the right side of the diaphragm is a little higher than the left side because of the liver below it. Many animals, like other mammals, also have diaphragms to help them breathe. Some animals, like amphibians and reptiles, have something similar to a diaphragm, though it might look different.

The diaphragm is the main muscle that helps us breathe. When we breathe in, the diaphragm contracts and moves down. This makes the space in our chest bigger and pulls air into our lungs. When the diaphragm relaxes and moves up, we breathe out.

Doctors can use an X-ray to look at the diaphragm and find any problems, like if parts of the belly move into the chest. This helps keep us healthy and safe.