Mediastinum

Mediastinum structure

The mediastinum represents anatomic space, median area of a thorax. In front the mediastinum is limited to a breast, and behind – a backbone. On each side from this body there are pleural cavities.

For various purposes (surgical intervention, planning of radiation therapy, the description of localization of pathology) the mediastinum, according to the scheme offered by Tvayning in 1938 is divided on upper and lower, and also front, back and average departments.

Front, average, postmediastinum

The front mediastinum is in front limited to a breast, behind – brachiocephalic veins, a pericardium and brachiocephalic trunk. In this space there are internal chest veins, a chest artery, lymph nodes of a mediastinum and a thymus gland – a thymus.

Structure of an average mediastinum: heart, venas cava, brachiocephalic veins and a brachiocephalic trunk, an aortic arch, the ascending aorta, phrenic veins, primary bronchi, a trachea, pulmonary veins and arteries.

The postmediastinum is limited to a trachea and a pericardium in a front part, in back – a backbone. In this part of body the gullet, the descending aorta, a chest lymphatic channel, semi-unpaired and unpaired veins, and also back lymph nodes of a mediastinum are located.

Upper and lower mediastinum

The upper mediastinum possesses all anatomical structures which lie above the upper edge of a pericardium: its borders are an upper aperture of a breast and the line drawn between a corner of a thorax and the intervertebral disk Th4-Th5.

The lower mediastinum is limited to the upper edges of a diaphragm and pericardium and, in turn, also shares on front, and back speak rapidly average.

Classification of new growths of a mediastinum

Not only true tumors of a mediastinum, but also tumorous diseases and cysts, excellent on etiology, localization and course of a disease, are considered as new growths of body. Each of new growths of a mediastinum comes from fabrics of various origin, combining only anatomic borders. They are subdivided on:

• Primary new growths;
• Secondary malignant tumors (metastasises of tumors of the bodies located in lymph nodes of a mediastinum);
• Tumors of the bodies entering a mediastinum;
• Tumors of fabrics whose task consists in restriction of a mediastinum;
• Pseudo-tumoral diseases (a disease of Benye-Beka-Shaumana, defeat of nodes of a mediastinum at tuberculosis, parasitic cysts, malformations of large vessels, etc.).

Clinical picture of new growths

Tumors of a mediastinum come to light preferential at young and middle age with an identical frequency, both at men, and at women. In spite of the fact that diseases of a mediastinum can not prove and be found a long time only on a preventive research, allocate several symptoms which characterize disturbances of this anatomic space:

• Not megalgias which are localized in the place of new growths and giving to a neck, a shoulder, interscapular area;
• The mydriasis, omission of a century, retraction of an eyeglobe – can arise in case of growth of a tumor in a boundary sympathetic trunk;
• The voice Osiplost – originates owing to damage of a recurrent guttural nerve;
• Weight, noise in the head, an asthma, stethalgias, cyanosis and puffiness of the person, swelling of veins of a thorax and neck;
• Disturbance of passing of food on a gullet.

At late stages of diseases of a mediastinum fervescence, the general weakness, an artralgichesky syndrome, disturbance of a cordial rhythm, hypostases of extremities are observed.

Mediastinum lymphadenopathy

The lymphadenopathy or hyperadenosis of this body are observed at carcinoma metastasises, lymphoma, and also some not tumoral diseases (a sarcoidosis, tuberculosis, etc.).

The main symptom of a disease is the generalized or localized hyperadenosis, however, the lymphadenopathy of a mediastinum can have such additional manifestations as:

• Fervescence, perspiration;
• Loss of body weight;
• Frequent infection of upper respiratory tracts (tonsillitis, pharyngitises, quinsies);
• Hepatomegalia and splenomegaly.

The damage of lymph nodes characteristic of lymphoma can be isolated, and combine itself germination of tumors in other anatomical structures (a trachea, vessels, bronchial tubes, a pleura, a gullet, lungs).