[-a-stahy-nuh] . Anatomy. 1535–45; < Neo-Latin; compare mediastīnus of middle class, apparently identical with Latin mediast(r)īnus a low-ranking slave, perhaps derivative of medius mid1, though sense and formation unclear
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Based on the Random House Dictionary, © Random House, Inc. 2012.
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| main air passage that branch from the trachea, carrying air to the lungs |
| muscular and cartilaginous structure lined with mucous membrane at the upper part of the trachea |
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mediastinum me·di·as·ti·num (mē'dē-ə-stī'nəm)
n. pl. me·di·as·ti·na (-nə)
A septum between two parts of an organ or a cavity.
The region in mammals between the pleural sacs, containing the heart and all of the thoracic viscera except the lungs. Also called interpleural space, mediastinal space.
me'di·as·ti'nal (-nəl) adj.
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mediastinum
the anatomic region located between the lungs that contains all the principal tissues and organs of the chest except the lungs. It extends from the sternum, or breastbone, back to the vertebral column and is bounded laterally by the pericardium, the membrane enclosing the heart, and the mediastinal pleurae, membranes that are continuous with those lining the thoracic cage. The mediastinum is a division of the thoracic cavity; it contains the heart, thymus gland, portions of the esophagus and trachea, and other structures. For clinical purposes it is traditionally divided into the anterior, middle, posterior, and superior regions
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