THE PERICARDIUM 



289 



aspects by the serous pericardium. A small pocket of the 

 pericardial sac, therefore, lies in front of the termination of 

 the superior vena cava (Fig. 105), and, when it is distended 

 with fluid, it may exercise pressure on the vessel, giving rise 

 to venous engorgement on both sides of the head and neck 

 and in both upper limbs. 



On each side, the pericardium is related to the medial 



^Ascending aorta 



Transverse sinus 

 -^'of pericardium 



Oblique sinus 

 "of pericardium 



,^-Epicardium 

 Serous layer 



of pericardium 

 '""Fibrous peri- 

 cardium 



FIG. 104. Diagram of a Sagittal Section through the Heart 

 and the Pericardium. 



surface of the lung from which it is separated by the medi- 

 astinal pleura. Pericardial effusions are sometimes so large 

 that they may compress the lungs and so superimpose pul- 

 monary dyspnoea on the existing cardiac dyspnoea. 



Posteriorly, the pericardium is related to the descending 

 thoracic aorta and to the oesophagus, which intervene between 

 it and the vertebral column. When food passes down the 

 oesophagus, the tube is bulged forwards and pressed against 

 the posterior aspect of the pericardium. In pericarditis, 

 '9 



