Epicardium: Definition, Function, Pericardial Membranes and Pericardial Disorders

The heart is an extraordinary organ; it is about the size of a closed fist, weighs about 10.5 ounces, and has the shape of a cone.

Along with the circulatory system, the heart works to supply blood and oxygen to all parts of the body.

The heart is located in the thoracic cavity just behind the sternum, between the lungs, and above the diaphragm. It is surrounded by a sac full of fluid called the pericardium, protecting this vital organ.

The heart wall comprises connective tissue, endothelium, and cardiac muscle. It is the heart muscle that allows the heart to contract and synchronize the heartbeat. The heart wall is divided into three layers: epicardium, myocardium, and endocardium.

  • Epicardium: an outer protective layer of the heart.
  • Myocardium: a muscular wall of the middle layer of the heart.
  • Endocardium:  inner layer of the heart.

Epicardium (epicardium) is the outer layer of the heart wall. It is also known as visceral pericardium since it forms the inner layer of the pericardium.

The epicardium is composed mainly of loose connective tissue, including elastic fibers and adipose tissue.

The pericardium is the sac filled with fluid surrounding the heart and the proximal ends of the aorta, vena cava, and pulmonary artery.


The heart and pericardium are located behind the sternum in the middle of the thoracic cavity, known as the mediastinum.

The pericardium serves as an outer protective covering of the heart, a vital organ of the circulatory and cardiovascular systems.

The primary function of the heart is to help circulate the blood to the tissues and organs of the body.

Function of the pericardium

The pericardium has several protective functions:

  • It keeps the heart contained within the thoracic cavity.
  • It prevents the heart from expanding too much when the blood volume increases.
  • It limits the movement of the heart.
  • Reduces friction between the heart and surrounding tissues.
  • Protects the heart against infection.

While pericardium provides several valuable functions, it is not essential for life. The heart can maintain a normal function without it.

Pericardial membranes

The pericardium is divided into three layers of membrane:

The fibrous pericardium is the external fibrous sac that covers the heart. It provides an outer protective layer attached to the sternum by sternopericardial ligaments.

The fibrous pericardium helps keep the heart inside the chest cavity. It also protects the heart from an infection that could spread from nearby organs, such as the lungs.

The parietal pericardium layer between the fibrous pericardium and the visceral pericardium. It is continuous with fibrous pericardium and provides an additional insulation layer for the heart.

The visceral pericardium is both the inner layer of the pericardium and the outer layer of the heart wall. Also known as the epicardium, this layer protects the heart’s inner layers and aids in the production of pericardial fluid.

The epicardium consists of elastic fibers of the connective tissue and adipose tissue (fat), which helps support and protect the inner layers of the heart.

Oxygen-rich blood is delivered to the epicardium and the inner layers of the heart by the coronary arteries.

Pericardial cavity

The pericardial cavity lies between the visceral pericardium and the parietal pericardium. This cavity is filled with pericardial fluid that serves as a buffer by reducing the friction between the pericardial membranes.

Two pericardial sinuses pass through the pericardial cavity. A breast is a passageway or channel.

The transverse pericardial sinus is placed above the heart’s left atrium, anterior to the superior vena cava, posterior to the pulmonary trunk, and the ascending aorta.

The oblique pericardial sinus is located posteriorly to the heart and is delimited by the inferior vena cava and the pulmonary veins.

Foreign Heart

The superficial layer of the heart (epicardium) is directly below the fibrous and parietal pericardium.

The outer surface of the heart contains grooves or grooves that provide conduits for the heart’s blood vessels. These grooves run along the lines separating the atria from the ventricles (atrioventricular groove).

As well as the right and left sides of the ventricles (interventricular groove). The main blood vessels that extend from the heart include the aorta, the pulmonary trunk, the pulmonary veins, and the venae cavae.

Pericardial disorders

Pericarditis is a disorder of the pericardium in which the pericardium becomes inflamed or swollen.

This inflammation interrupts the normal function of the heart. Pericarditis can be acute (occurs suddenly and quickly) or chronic (occurs over time and lasts a long time).

Some causes of pericarditis include bacterial or viral infections, cancer, kidney failure, certain medications, and heart attack.

Pericardial effusion is caused by the accumulation of large amounts of fluid between the pericardium and the heart. This condition can be caused by several other conditions that affect the pericardium, such as pericarditis.

Cardiac tamponade is the buildup of pressure in the heart due to excessive accumulation of fluid or blood in the pericardium.

This excess pressure does not allow the cardiac ventricles to expand ultimately. As a result, the cardiac output is reduced, and the blood supply to the body is insufficient.

This condition is most commonly caused by hemorrhage due to penetration of the pericardium.

The pericardium can be damaged due to severe chest trauma, a knife or bullet wound, or an accidental puncture during a surgical procedure.

Other possible causes of cardiac tamponade include cancer, heart attack, pericarditis, radiation therapy, kidney failure, and lupus.