1. Relationships of the heart to other structures in mediastinum
    1. Thorax is divided into the superior mediastinum and inferior mediastinum.
    2.  Inferior mediastinum:

      i.      Anterior mediastinum: extends from posterior surface of sternum to anterior surface of pericardial sac

  1. Fat
  2. Thymus gland (infants)
  3. Lymph nodes

   ii.      Middle mediastinum

  1. HEART
  2. Pericardium
  3. Main bronchi
  4. Great vessels
  5. Phrenic nerves

   iii.      Posterior mediastinum: Located posterior to the pericardial sac and diaphragm and anterior to vertebral bodies T5-T12

  1. Thoracic aorta
  2. Esophagus
  3. Azygous venous system
  4. Thoracic duct
  5. Vagus nerves
  6. Splanchic nerves