Topography. 



175 



517. Topography of the Thoracic Viscera. 



The pericardium is covered in front by the pleurae and the mar- 

 gins of the lungs, behind it rests upon the bronchi, oesophagus and 

 descending aorta. After opening of the pericardium a part of the large 

 vessels is found enclosed in its cavity. The aorta, the superior vena cava, 

 the four pulmonary veins and the right and left divisions of the pulmonary 

 artery, receive each an investment from the fibrous layer of the pericardium. 

 The space between heart and pericardium contains a small quantity of 

 Liquor Pericardii. 



