Posterior Mediastinum

mediastinum posterius

The posterior mediastinum lies behind the pericardium and in front of the lower thoracic vertebrae. It is a pathway for structures travelling between the neck, chest and abdomen, including the oesophagus, descending aorta, thoracic duct and azygos veins. It continues upwards with the superior mediastinum.

Anatomical Data

Structure & Supply

Location	Inferior mediastinum, behind the pericardium and above the diaphragm, in front of the bodies of T5-T12, between the mediastinal pleurae.
Parts	Oesophagus and oesophageal plexus Descending thoracic aorta Azygos and hemiazygos veins Thoracic duct Vagus nerves Sympathetic trunks and thoracic splanchnic nerves (paravertebral) Posterior mediastinal lymph nodes
Blood Supply	Oesophageal and mediastinal branches of the thoracic aorta; Posterior intercostal arteries
Lymphatic drainage	Posterior mediastinal nodes

Biomechanics

Function & Actions

Provides a protected channel linking the neck and abdomen for food, blood, lymph and nerve signals.

Clinical Relevance

Clinical Notes

Most posterior mediastinal masses are nerve tumours arising from the sympathetic chain or intercostal nerve roots. Oesophageal perforation, for example after forceful vomiting, leaks into this space and causes mediastinitis. Aneurysms and dissections of the descending aorta also lie here.

Pathology

Common Injuries & Conditions

Neurogenic Tumour

Tumours such as schwannoma, neurofibroma or ganglioneuroma arising from nerves in the paravertebral region. They are often benign in adults.

Boerhaave Syndrome

Full-thickness rupture of the oesophagus, usually after violent vomiting. Contents leak into the posterior mediastinum and cause severe chest pain and sepsis.

Descending Aortic Aneurysm

Dilation of the thoracic aorta, often silent until it presses on nearby structures or ruptures. Dissection causes severe tearing back pain.

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