[mee-dee-a-stahy-nuh
m] 
[-a-stahy-nuh] . Anatomy. | 1. | a median septum or partition between two parts of an organ, or paired cavities of the body. |
| 2. | the partition separating the right and left thoracic cavities, formed of the two inner pleural walls, and, in humans, comprising all the viscera of the thorax except the lungs. |
| me·di·as·ti·num (mē'dē-ə-stī'nəm) n. pl. me·di·as·ti·na (-nə) The region in mammals between the pleural sacs, containing the heart and all of the thoracic viscera except the lungs. [New Latin mediastīnum, from neuter of Medieval Latin mediastīnus, medial, from Latin, inferior servant, drudge (anatomical sense probably influenced by Latin intestīnum, intestine), from medius, middle; see medhyo- in Indo-European roots.] me'di·as·ti'nal (-nəl) adj. |
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.