The mediastinum is the area of the thorax located between the two pleural sacs and encloses most of the organs found in the thorax. The mediastinum can be split into the superior and inferior mediastinum. The inferior mediastinum itself can be further divided into the anterior, middle and posterior mediastinum, which all lie between the sternal angle and the diaphragm.
The superior mediastinum is the area of the thorax above the sternal angle (at the level of the T4 vertebra) and between the thoracic aperture. Some of the contents of the superior mediastinum include the arch of the aorta, the superior vena cava, the trachea and the vagus nerve.
The middle mediastinum sits behind the anterior mediastinum and in front of the posterior mediastinum. The middle mediastinum contains the heart as well as the origins of its great vessels. Furthermore, the trachea notably bifurcates in here to form the right and left main bronchi.
The anterior mediastinum lies in front of the middle mediastinum and contains no major structures whereas the posterior mediastinum contains the thoracic aorta, oesophagus, thoracic duct, azygos system of veins, as well as the sympathetic trunks.
In this section, learn more about the areas of the thorax– the superior mediastinum, the anterior mediastinum, the middle mediastinum and the posterior mediastinum.
