The pericardium and the pericardial sinuses

Pericardium: (Peri-around, Cardium-heart)

It is a double-walled, fluid filled sac. It contains the heart and the juxtacardiac parts of its

great vessels(the aorta, the vena cava and the pulmonary artery).

Functions of the pericardium:

Keeps the heart contained in the thoracic cavity(cardiac seat belt).

Prevents over-expanding of heart when blood volume increases.

Limits the heart’s movements.

Acts as a shock absorber with the help of the fluid filled sac.

Pericardium

Inner Serous layer

Inner visceral

Outer Parietal

Outer Fibrous layer Single Layer

FIBROUS PERICARDIUM: The fibrous pericardium is a sac made of

tough connective tissue It is roughly conical and clothes the heart. Attachments: Superiorly, it is continuous with the adventitia

of the great vessels and also the pre-tracheal fascia.

Inferiorly, it is attached the the central tendon of the diaphragm and a small muscular part of its left side.

Anteriorly, it is attached to the posterior surface of the sternum by superior and inferior sternopericardial ligaments. The extents of these ligaments are extremely variable and the suerior one is often undetectable.

The pericardium is securely anchored by these attachments and maintains the general thoracic position of the heart, serving as the cardiac seat belt’.

Relations: Anteriorly, Seperated from the thoracic wall by the lungs

and the pleural coverings. But,in a small area behind the lower left

halfof the body of the sternum and the sternal ends of the left 4th and 5th costal cartilages , the pericardium is in direct contact with the thoracic wall.

Until it regresses, the lower end of the thymus is anterior to the upper part.

Posteriorly, The principal bronchi, the esophagus, the

esophageal plexus, the descending thoracic aorta, and the posterior parts of the mediastinal surface of both lungs.

Laterally, Pleural coverings of the mediastinal surface

of the lungs. The phrenic nerve with its accompaning

vessels, descends between the mediastinal pleura and the fibrous pericardium on either side.

Inferiorly, the pericardium is seperated from the liver and

the fundus of stomach by the diaphragm.

The aorta, the superior vena cava, the pulmonary arteries and veins receive extensions of the fibrous pericardium except the inferior vena cava which traverses the central tendon.

SEROSAL PERICARDIUM: It is closed sac within the fibrous

pericardium and has a visceral and a parietal layer.

The visceral layer or the epicardium covers the heart and the great vessels and is reflected into the parietal layer which lines the inner surface of the fibrous pericardium.

The reflections of the serosal layer are arranged as two complex tubes : the aorta and the pulmonary trunk are enclosed min one and the superior and inferior vena cavae and the pulmonary veins in the other.

The tube surrounding the veins has an inverted J shape.

The cul-de-sac within its curve is behind the left atrium and is termed the ‘OBLIQUE SINUS’.

The passage between the two pericardial tubes is termed the ‘TRANSVERSE SINUS’.

Vascular supply and lymphatic drainage:• The arteries are derived from the internal

thoracic, the musculophrenic arteries and the descending thoracic aorta.

• The veins are tributaries of the azygous system.

Innervation:• The pericarduium is innervated by the vagus,

together with the phrenic nerves and the sympathetic trunks

Applied aspects:

Pericardial effusion: • Accumulation of excess fluid in the

pericardial space.• When this obstructs the beating of

heart, it is termed cardiac tamponade.• Symptoms are severe edema, low BP,

shortness of breath, dizziness, chest pain, cough, rapid pulse.

• Causes are inflammation, rheumatoid arthritis, surgery, cancer, infection, kidney failure, hemorrhage, trauma or idiopathic.

• Treatment: Giving NSAIDS, excess fluid drained using a needle or in severe cases, surgery.

PERICARDITIS:• Inflammation of the pericardium. • Infections that can cause pericarditis include

viral infections, bacterial infections, tuberculosis, and fungal infections. Patients with AIDS frequently develop infections that produce pericarditis.

Autoimmune disorders that can cause pericarditis include rheumatoid arthritis, lupus, and scleroderma.

Pericarditis occurs in up to 15% of patients who have acute myocardial infarctions (heart attacks). There is also a late form of post-heart-attack pericarditis, called Dressler’s syndrome, that occurs weeks to months after the heart attack.

• Some of the drugs that can produce pericarditis include procainamide, hydralazine, phenytoin, and isoniazid.

• Many forms of cancer can metastasize (spread) to the pericardial sac, and produce pericarditis.In many cases, no definite cause for pericarditis can be identified - this is called “idiopathic" pericarditis.”

• The most common symptom caused by pericarditis is chest pain. The pain can severe, and is often made worse by changing position or with deep breathing. Patients can also have shortness of breath, or fever.

• Pericarditis can produce complications, namely tamponade, chronic pericarditis, and constriction. These complications - which are discussed below – can produce reduced cardiac pumping, lung congestion, and organ failure.

• Acute pericarditis is treated by a) identifying the underlying cause, b) treating the underlying cause, c) giving anti-inflammatory drugs (to reduce inflammation and help prevent chronic problems), and d) giving analgesics to control the pain. Most cases of acute pericarditis resolve within a few weeks, and leave no permanent cardiac problems.

• Tamponade is treated by draining the fluid from

the pericardial sac, usually via a tiny catheter. Removing the fluid relieves the pressure on the heart, and restores normal cardiac function almost immediately.

• Chronic pericarditis is treated by identifying and treating the underlying cause, if possible. If recurrent pericardial effusions become a problem, surgery can be done to create a permanent opening that allows the fluid to drain from the pericardial sac, thus preventing tamponade.

• Constrictive pericarditis is a very difficult

therapeutic problem. Symptoms can be treated with bed rest, diuretics, and digitalis, but definitive treatment requires surgery to strip the thickened pericardial lining from the heart. This surgery is usually quite difficult

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