The mediastinum is the central portion of the thoracic cavity located between the lungs. It is divided into the superior mediastinum above the sternal angle and inferior mediastinum below. The inferior mediastinum is further divided into the anterior, middle, and posterior mediastinum, with the middle mediastinum containing the heart and pericardium.

1. Mediastinum

2. The median portion of the thoracic cavity (interpleural) Limited by: Thoracic inlet superiorly Diaphragm inferiorly Sternum anteriorly 12 Thoracic vertebrae posteriorly Mediastinum

3. Sternal Angle Thoracic inlet Thoracic oulet

4. Mediastinum It is divided into: 1. Superior mediastinum: lies between the first rib and the sternal angle. 2. Inferior mediastinum: lies between the sternal angle and the diaphragm.

5. Mediastinum Inferior mediastinum: is subdivided into: Anterior mediastinum Middle mediastinum Posterior mediastinum

6. Superior Mediastinum Posterior Mediastinum Anterior Mediastinum Middle Mediastinum Sternal Angle L4 L5

7. Superior Mediastinum It contains: Blood vessels (large veins & arteries) Thoracic duct Trachea Esophagus Thymus Nerves

8. Superior Mediastinum Blood Vessels Superior vena cava Brachiocephalic veins Pulmonary trunk Arch of Aorta

9. Superior Mediastinum Nerves Vagus nerve Left Recurrent Laryngeal nerve. Phrenic nerve.

10. Inferior Mediastinum Anterior mediastinum: contains: Thymus gland Lymph Nodes Fat.

11. Inferior Mediastinum Middle mediastinum: contains: Heart Pericardium Phrenic nerve Main bronchi

12. Inferior Mediastinum Posterior mediastinum: contains: Esophagus Thoracic aorta Azygus vein Thoracic duct Vagus nerve Sympathetic trunk