Pericardium
Anatomy
The human pericardium is a double-walled sac containing the heart and the roots of the great vessels. The pericardium anchors the heart to the surrounding structures, prevents overfilling of the heart with blood, and plays a role in the physiological function of the heart and major blood vessels.
The pericardium is made up of two layers: the fibrous pericardium and the serous pericardium. The fibrous pericardium is the outermost layer and is made of dense and unyielding fibrous tissue. The serous pericardium, on the other hand, is a thinner, more delicate membrane that forms a double layer around the heart.
Fibrous Pericardium
The fibrous pericardium is the most superficial layer of the pericardium. It is a tough, inelastic, dense, and fibrous connective tissue that protects the heart, anchors it to its surrounding structures, and prevents overdistension (overfilling with blood). The fibrous pericardium is attached to the central part of the diaphragm and the posterior part of the sternum, which are two of the main structures that the heart sits between.
Serous Pericardium
The serous pericardium is a thinner, more delicate membrane that forms a double layer around the heart. It is divided into two layers: the parietal layer, which is fused to the fibrous pericardium, and the visceral layer, or epicardium, which is fused to the heart and is part of the heart wall. The serous pericardium secretes a thin, watery fluid (pericardial fluid) into the pericardial cavity, the space between the parietal and visceral layers. This fluid serves to reduce friction between the layers of the pericardium as the heart beats.
Pericardial Fluid
Pericardial fluid is a serous fluid secreted by the serous layer of the pericardium into the pericardial cavity. The primary function of this fluid is to reduce friction between the heart and the pericardium. The amount of fluid in the pericardial cavity is usually small, ranging from 15 to 50 milliliters in a healthy individual. However, the volume can increase significantly in certain pathological conditions, such as pericardial effusion.
Pericardial Effusion
Pericardial effusion is a pathological condition characterized by an abnormal accumulation of fluid in the pericardial cavity. It can be caused by a variety of conditions, such as infection, inflammation, heart surgery, or cancer. The increased volume of fluid can compress the heart and affect its function, a condition known as cardiac tamponade.
Cardiac Tamponade
Cardiac tamponade is a serious medical condition in which the accumulation of fluid in the pericardial cavity compresses the heart and impairs its ability to pump blood. This can lead to a decrease in blood pressure, shock, and if left untreated, death. The treatment for cardiac tamponade often involves a procedure called pericardiocentesis, in which a needle is inserted into the pericardial cavity to drain the excess fluid.
Pericardiocentesis
Pericardiocentesis is a medical procedure in which a needle is inserted into the pericardial cavity to remove excess fluid. This procedure is typically performed under ultrasound guidance to ensure accurate placement of the needle. Pericardiocentesis can be performed as an emergency procedure to treat cardiac tamponade, or it can be performed as a diagnostic procedure to determine the cause of a pericardial effusion.