Boundaries

Anterior: ( a) pericardium and its contents, (b) bifurcationof the trachea, and (c) pulmonary vessels.

Posterior: Bodies of lower 8 thoracic vertebrae andintervening intervertebral discs.

Superior: Transverse thoracic plane separating superiormediastinum from the inferior mediastinum.

Inferior: Diaphragm.

On every side: Mediastinal pleura.

Contents

1) Esophagus.

2) Thoracic duct.

3) Descending thoracic aorta and its branches.

4) Azygos, hemiazygos, and accessory hemiazygos veins.

5) Vagus nerves.

6) Sympathetic trunks and splanchnic nerves.

7) Posterior mediastinal lymph nodes.