mediastinumiin

The mediastinum is the central compartment of the thoracic cavity, located between the two pleural sacs. It extends from the superior thoracic aperture to the diaphragm and from the sternum to the vertebral column. Traditionally it is divided into a superior mediastinum and an inferior mediastinum, with the latter further subdivided into anterior, middle, and posterior parts.

The superior mediastinum contains structures such as the thymus (more prominent in children), the aortic arch and its branches, the superior vena cava, the trachea, the esophagus, the thoracic duct, and several nerves and lymph nodes. The middle mediastinum houses the heart within the pericardium, the roots of the great vessels, and portions of the trachea and bronchi. The anterior mediastinum lies between the sternum and pericardium and can contain connective tissue and, in younger individuals, thymic tissue. The posterior mediastinum contains the esophagus, thoracic aorta, thoracic duct, and sympathetic nerves.

The mediastinum serves as a conduit for air, food, blood vessels, nerves, and lymphatics, and houses critical organs and vessels essential for cardiopulmonary function. Its contents make it a frequent site for pathology, including masses and inflammatory processes.

Clinical significance includes mediastinitis, an often serious infection that can follow surgery or spread from nearby infections, presenting with chest pain and fever. Mediastinal masses may be thymomas, teratomas, lymphomas, or other tumors, and require imaging and sometimes biopsy to characterize. Imaging typically begins with chest radiography and is followed by CT; MRI or PET-CT may be used for further assessment.

Management depends on the underlying condition and may involve antibiotics, surgical drainage, oncologic therapy, or surgical resection of tumors, with prognosis varying by cause and stage.