Summary

Mediastinal anatomy

The mediastinum is the thoracic space between the visceral pleura of the lungs. The boundaries of the mediastinum are the visceral pleura, thoracic inlet (spine, first ribs, and manubrium), diaphragm, sternum, and anterior spinal ligaments. View image The contents of the mediastinum include the heart, great vessels, trachea, oesophagus, lymphatic tissue, and thymus gland. Tumours may arise from any of these organs. The mediastinum is divided into 4 compartments: superior, anterior, middle, and posterior. View image

Mediastinal contents

Superior mediastinal contents include:

• Upper third of the thoracic oesophagus

• Great vessels

• Trachea

• Upper poles of the thymus gland

• Paratracheal lymph nodes

• Descended thyroid.

Anterior mediastinal contents include:

• Mediastinal fat

• Lymph nodes

• Body and lower poles of the thymus

• Extracardiac aorta.

Middle mediastinal contents include:

• Pericardium and heart

• Trachea and carina

• Lymph nodes.

Posterior mediastinal contents include:

• Oesophagus

• Descending aorta

• Thoracic duct

• Sympathetic nerve chain.