Middle mediastinum

The middle mediastinum is the broadest part of the interpleural space.

Contents
It contains:
 * the heart enclosed in the pericardium
 * the ascending aorta
 * the lower half of the superior vena cava with the azygos vein opening into it
 * the bifurcation of the trachea and the two bronchi
 * the pulmonary artery dividing into its two branches
 * the right and left pulmonary veins
 * the phrenic nerves
 * some bronchial lymphatic glands