Topography. 



53 



389. Topography of the Posterior Mediastinum, 



The left Lung and Heart are turned to the right. 



The two lungs and the inner surface of the thorax are invested 

 by serous membranes, the two pleurae; the portion investing the sur- 

 face of the lung is called the Pleura pulmonalis, while that which lines 

 the inner surface of the chest is called the Pleura costalis (Fig. 888)5 

 that part of the Pleura costalis which comes in contact with the upper 

 surface of the diaphragm is called Pleura plirenica. The third serous 

 membrane in the thorax covers the heart and commencement of the great 

 vessels, and is called pericardium. The space left in the median line 

 of the chest by the non-approximation of the two pleurae is called the 

 mediastinal space, Cavum mediastini , or simply mediastinum. 

 The part of this space in front of the pericardium is called the anterior 

 mediastinum, Cavum mediastini anterius, and that behind the pericardium, 

 the posterior mediastinum, Cavum mediastini posterius. 



