Glossary of Terms
The mediastinum is the "middle" section of the chest cavity. The chest cavity contains the left and right lungs, which lie on either side of the heart. The heart is contained in the portion of the chest known as the mediastinum. The mediastinum is bordered by the thoracic inlet (where the organs of the neck enter the chest) on top, by the diaphragm on the bottom, the sternum (breastbone) in front, and the vertebral column (backbone) to the rear. The mediastinum is artificially divided into the anterior, middle and posterior sections. The mediastinum contains all of the chest organs except the lungs. Organs located in the mediastinum include the heart, the aorta, the thymus gland, the chest portion of the trachea, the esophagus, lymph nodes and important nerves.