What Is the Pericardial Sac?
The pericardial sac is a double walled layer of tissue which surrounds the heart and the large blood vessels which supply it. It acts essentially like a protective envelope for the heart, permitting normal heart movement within the confines of the sac while insulating the heart and great blood vessels. The outer layer of the pericardial sac is attached to the diaphragm and the sternum to anchor it in place.
