Some of the most vital organs of humans are located in the thoracic cavity, including the lungs and the heart. HowStuffWorks explains that when a person inhales, the diaphragm and muscles between the ribs expand the thoracic cavity to reduce the pressure inside the body to a level that is lower than the pressure of the air outside the body. As a result, the lungs pull air through the body's airways.
Innerbody describes the heart as a muscular organ that serves as the body's circulatory pump in the thoracic cavity. The upper end of the heart is attached to the aorta, vena cava and the pulmonary arteries and veins. Its lower tip, or apex, is just above the diaphragm. The base is located along the vertical centerline, but it is angled to the individual's left, with two-thirds of its mass on the left of the body and the remaining one-third on the right.
The rib cage surrounds the thoracic cavity, providing protection for these vital organs, according to Reference.com. This cavity also includes the serous membrane, a tissue that serves to protect the vital organs in the chest. The visceral pleura lines the heart, but the same membrane also extends to cover the lungs, esophagus and major blood vessels in the chest.