Diaphragm

Definition

The diaphragm is a dome-shaped sheet of muscle and tendon that serves as the primary muscle for respiration, separating the thoracic (chest) cavity from the abdominal cavity. It contracts and flattens when you inhale, allowing the lungs to expand and fill with air, and relaxes and domes upwards during exhalation, pushing air out of the lungs.

Related terms

Intercostal muscles: These are several groups of muscles located between the ribs that assist in breathing by raising and lowering the rib cage.

Abdominal muscles: A group of muscles in the abdomen that, among other functions, work together with the diaphragm to aid in breathing, particularly during forceful exhalation.

Thoracic cavity: The part of the body enclosed by the ribs, above the diaphragm, containing primarily lungs and heart