Evaluation of mediastinal mass

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. The contents of the mediastinum include the heart, great vessels, trachea, esophagus, thymus gland, lymphatic tissue, and nerves. Tumors may arise from any of these structures. The mediastinum is commonly divided into the anterior, middle, and posterior compartments. Occasionally, radiographic or anatomic texts may refer to a superior compartment, which adds little to clinical management.[Figure caption and citation for the preceding image starts]: Borders of the mediastinumFrom the collections of Dr Mario Gasparri and Dr Nicholas Choong [Citation ends].[Figure caption and citation for the preceding image starts]: Anatomic compartments of the mediastinum.From the collection of Dr Muniappan [Citation ends].

Mediastinal contents

Anterior mediastinal contents include:

• Thymus gland

• Mediastinal fat

• Lymph nodes

• Extracardiac aorta.

Middle mediastinal contents include:

• Pericardium, heart, ascending and descending aorta, great vessels

• Trachea and carina

• Lymph nodes

• Esophagus

• Vagus nerves

• Thoracic duct.

Posterior mediastinal contents include:

• Proximal intercostal vessels

• Thoracic spinal ganglion

• Sympathetic nerve chain

• Lymph nodes.