Answer
The structures that make up the thoracic cage are the thoracic vertebrae, the sternum, the ribs, the intercostal muscles, and the diaphragm. The general shape of the structure is conicical-- with a broad base and narrower superior apex. The main contents of the cage are the heart and the lungs. It is attached to the pectoral girdle at the sternum and is bordered inferiorly by the costal margin of the arc of the lower ribs.
The thoracic cage protects, the heart, the lungs, and the large blood vessels as well as the spleen, parts of the liver and parts of the kidneys.
Work Step by Step
The thorax also has an important respiratory function. It expands during the act of inspiration, thus creating a vacuum that causes air to rush into the lungs. At the end of inspiration, the weight of the ribs and the elasticity of the intercostal muscles cause the thoracic space to constrict passively, and air is pressed out of the lungs in the act of expiration.
