2.0 DESCRIPTION
The mediastinum involves the
mass of tissues and organs separating the two lungs, between the sternum
in front and the vertebral column behind, and from the thoracic
inlet above to the diaphragm below. It contains the heart and its
large vessels, the trachea, esophagus, thymus, lymph nodes, and other
structures and tissues. The diaphragm involves the musculomembranous
partition separating the abdominal and thoracic cavities, and serves
as a major inspiratory muscle.