Mediastinum


Also found in: Dictionary, Thesaurus, Medical, Wikipedia.

mediastinum

[‚mē·dē·ə′stī·nəm]
(anatomy)
A partition separating adjacent parts.
The space in the middle of the chest between the two pleurae.

Mediastinum

 

in man, an anatomic area in the thoracic cavity, bounded anteriorly by the sternum, posteriorly by the thoracic region of the spine, laterally by the pleurae and lung surfaces, and inferiorly by the diaphragm; an arbitrary horizontal line drawn across the upper edge of the sternum is considered to be the upper boundary.

A distinction is made between anterior and posterior mediastinal regions, which are divided by the roots of the lungs. The anterior mediastinum contains the heart and heart sac (the pericardium), the ascending aorta and its arch (including the arteries issuing from them), the pulmonary trunk, the venae cavae, the pulmonary veins, and the phrenic nerves. The posterior mediastinum contains the thoracic portion of the descending aorta and its branches, the esophagus, the azygos and hemiazygos veins, the thoracic lymphatic duct, and the vagus and splanchnic nerves.

Closed injuries of mediastinal organs occur in cases of contusions, compression of the chest, and sternal fractures. Upon injury to the lungs or bronchi and the accumulation of air, pneumomediastinum and the compression of mediastinal organs may occur. Open mediastinal injuries are associated with injuries of the lungs and often of the organs of the abdominal cavity. Mediastinal injuries are treated surgically. The most common diseases of the mediastinum include mediastinitis, substernal extension of an enlarged thyroid gland, cysts and tumors of mediastinal organs, and lesions of mediastinal lymph nodes, for example, in cases of lymphogranulomatosis.

REFERENCES

Petrovskii, B. V. Khirurgiia sredosteniia. Moscow, 1960.
Elizarovskii, S. I., and G. I. Kondrat’ev. Khirurgicheskaia anatomiia sredosteniia (atlas). Moscow, 1961.
Gol’bert, Z. V., and G. A. Lavnikova. Opukholi i kistv sredosteniia. Moscow, 1965. ’
References in periodicals archive ?
In his yearly routine medical examination, chest CT (August 04, 2016) revealed a cystic mass in the posterior mediastinum.
5] The other sites are sublingual, prelaryngeal, intratracheal, oesophagus, mediastinum, gall bladder, porta hepatis, salivary glands etc.
1-6) There are various methods of dividing the mediastinum into compartments by radiologists, pathologists, anatomists and surgeons.
The rate of teratomas that have been observed to arise in the posterior mediastinum or the ones that extend to the posterior mediastinum is only 3%.
On ultrasound exam they present as single unilocular, echo-free cystic structures within lung parenchyma or within the posterior mediastinum.
A ciliated cyst in the posterior mediastinum compatible with a paravertebral Mullerian cyst.
Thymoma is the most common tumor in the anterior mediastinum with germ cell tumors, lymphoma, thymic cysts, and thymic hyperplasia accounting for the majority of the rest (1, 3).
The mediastinum was widened due to haemothorax, which was drained by chest tubes.
The most common location was anterior or posterior mediastinum.
Hyaline-vascular and plasma-cell types of giant lymph node hyperplasia of the mediastinum and other locations.
The CXR is an easily accessible imaging tool, and despite its limitations it can demonstrate mediastinal emphysema (pneumomediastinum and pneumopericardium) clearly as air contrasts well with the soft tissue of the mediastinum.
1) With this technique, early division of anterior tracheal attachments and mobilization of the superior pole facilitates removal of the inferior pole from the mediastinum.