Diaphragm (anatomy)

In the anatomy of mammals, the diaphragm is a shelf of muscle extending across the bottom of the ribcage. It separates the thoracic cavity (with lung and heart) from the abdominal cavity (with liver, stomach, intestines, etc.). In its relaxed state, the diaphragm is shaped like a dome. It is critically important in respiration: in order to draw air into the lungs, the diaphragm contracts, thus enlarging the thoracic cavity and reducing intra-thoracic pressure. (The muscles between the ribs also participate in this enlargement.) When the diaphragm relaxes, air is exhaled by elastic recoil of the lung and the tissues lining the thoracic cavity.

External links

• Gray's anatomy, muscles of the thorax