Function of mediastinum

It is a space between the lungs, left and right, and the bony structures in front (sternum) and in back (thoracic vertebrae). It is classically divided into three parts radiologically on a lateral chest x-ray, the anterior (in front of the heart), middle (front edge of the heart to junction of the anterior third - posterior two thirds of the thoracic vertebrae) and posterior mediastinum. It contains the heart, major blood vessel's, trachea and esophagus, lymph nodes and nerves as well as the thymus.