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 ?
The letter by Dr Walker (based on the findings reported by Grinberg et al (3)) describes anthrax toxins causing extensive tissue injury and hemorrhage of the mediastinum resulting in the characteristic radiographic mediastinal widening.
It is most unusual for this tumor to present in the mediastinum as a primary solitary lesion.
The patient had undergone an MRI evaluation, which indicated a cyst of 3x4cm in size in the upper right mediastinum with a paratracheal location.
In most cases, hyperplasia is in the mediastinum, but exceptional localizations may be seen.
Once a perforation occurs, saliva, retained gastric contents, bile, and acid enter the mediastinum, resulting in mediastinitis.
The first, involved a "malpositioned catheter, which [allegedly] migrated extravascularly caused fluid to accumulate in the mediastinum and both pleural spaces that ultimately led to acute respiratory failure.
One single FDG-PET showed an infection in the mediastinum," he said.
VERSION 1: "You have a lesion in your mediastinum that is two centimeters.
He then orders a chest X-ray, which is read by him and the radiologist as showing no pneumothorax and a central line in the mediastinum.
In one patient in whom the primary lesion was on the lace, the postmortem findings included extensive edema of the neck, soft tissues of the chest, and the mediastinum (2).
Each patient in this group had a negative metastatic work-up, but FDG-PET scans were able to determine if breast cancer had spread to mediastinum, liver, bone, or axillary lymph nodes.
An anteroposterior chest radiograph showed pneumomediastinum tracking along the left cardiac border and superiorly in the bilateral soft tissues of the upper mediastinum and neck (Figure 1a).