15. The anatomy of the thorax

The anatomy of the thorax comprises the content of the thoracic cavity and the thoracic cage/rib cage. The thoracic cavity contains the trachea and main bronchi, the lungs, the heart, the great arteries, the large veins, the mediastinum and the oesophagus. The thoracic cage comprises the sternum, the ribs and the clavicle, which is connected to the scapula at the back of the thorax by the pectoral girdle. Between the ribs are the intercostal spaces, each of which is named after the rib above it. The most commonly used reference point is the sternal angle, palpable as an irregular line, to which the second rib is attached at the side. Imaginary vertical lines on the thorax can be used to locate the organs in the thoracic cavity.