What does the diaphragm do?

The diaphragm is a dome-shaped muscle located at the base of the thoracic cavity, and its primary function is to facilitate breathing. During inhalation, the diaphragm contracts and moves downward, which increases the volume of the thoracic cavity and decreases the pressure within it. This pressure change allows air to flow into the lungs. Conversely, during exhalation, the diaphragm relaxes and moves back to its original position, helping to push air out of the lungs. This process is essential for respiration, making the diaphragm a critical component in the mechanics of breathing.

While the diaphragm does contribute to abdominal support by creating a physical barrier between the thoracic and abdominal cavities, and it plays a role in protecting the lungs by aiding in proper lung expansion and contraction, its defining and most important role is in facilitating the process of breathing.