Mediastinum


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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 ?
Median sternotomy was done and the mass was found lying in antero-superior mediastinum adherent to mediastinal pleurae and pericardium covering SVC and right ventricle (Figure-3).
Prognosis is generally good and depends on the amount of the air in the mediastinum and underlying etiological factors.
Primary mediastinal lymphomas usually occur in anterior mediastinum and account for 20% of neoplasms in adults and about 50% in paediatric age group [3,8,15] which correlates with the present study.
The lymph node metastasis rates of mid-thoracic ESCC in the middle mediastinum, lower-thoracic ESCC in the lower mediastinum and abdominal cavity were 18.5%, 35.3% and 19.7% respectively in the T1-T2 stage.
In our case, the patient was diagnosed with spontaneous PM due to the presence of free air bubbles in mediastinum and under the skin as observed in the PA chest X-ray and CT scan.
Parathyroid glands are rarely located in the mediastinum, which are often removed through sternotomy or thoracotomy (<1% - 3%) (3).
In this study, the research on voice and swallowing functions was delimited in individuals with tumors in the mediastinum.
Including our case, only 15 cases of pulmonary stenosis because of extrinsic compression by a teratoma in the anterior mediastinum have been reported.
Pneumomediastinum was described by Laennec in 1819 while spontaneous mediastinum was described by Hamman in 1939.
The patient was brought to 30 degrees semi-supine position if the lesion was located in the anterior mediastinum. Due to our experience in video-assisted thoracoscopic surgery (VATS) thymectomy, in patients for which we prefer the right-sided approach in robotic excision of anterior mediastinal lesions, the patients were supported with a roll under the right shoulder and then, the right arm was brought below the level of rib cage [Figure 1].
Parathyroid cysts are rare lesions of the neck and mediastinum with a peak incidence in the fourth and fifth decades of life.
Several theories have been proposed to explain the histogenesis of Mullerian cysts in the mediastinum. Hattori (2) suggested that the cysts may be derived from misplaced mesothelium and mesenchyme with Mullerian characteristics similar to retroperitoneal Mullerian cysts.