The pericardium is the sac, or pouch, which wraps the heart and the roots of the great blood vessels. It consists of two layers; an external parietal layer, which is the pericardium proper, and an internal visceral layer, which is called the epicardium. The epicardium snugly envelops the myocardium.
The pericardium proper is composed, in turn, of an internal serous sheet, and an external fibrous layer. This sac-like structure surrounding the heart is shaped like a beveled cone, whose lower base lies on the diaphragm, with the apex almost reaching the level of the angle of sternum. Like the heart, it extends in breath more to the left than to the right. The superior sternopericardial ligament attaches the anterior part of pericardium to the manubrium sterni (upper portion of sternum).
The base of the pericardium, or inferior part, is intimately fused with the central tendon of diaphragm. It extends slightly over the front left areas of the muscular part of diaphragm, to which it is attached by areolar tissue. The anterior part faces the anterior wall of thorax and is in relation with the body of sternum, intercostal spaces, and the left portion of the xiphoid process.
The lateral parts (right and left) of pericardium are the mediastinal parts. They adjoin the mediastinal pleura, which is connected to it also by areolar tissue.
