Anatomy of Pericardium

1. PERICARDIUM Prepared by: Sharmin Susiwala

2. The  pericardium is a double-walled conical fibro-serous sac, in which the heart and the roots of the great vessels are contained.

3. BOUNDARIES : In   front: It is separated from the anterior wall of the thorax, by the lungs and pleuræ and usually corresponding with the left half of the lower portion of the body of the sternum and the medial ends of the cartilages of the fourth and fifth ribs of the left side Behind: It rests upon the bronchi, the esophagus, the descending thoracic aorta, and the posterior part of the mediastinal surface of each lung.  Laterally:   It is covered by the pleuræ , and is in relation with the mediastinal surfaces of the lungs; the phrenic nerve, with its accompanying vessels, descends between the pericardium and pleura on either side.

4. Structure of Pericardium There are two layers to the pericardial sac: Outermost fibrous pericardium Inner serous pericardium

5. Fibrous pericardium: The fibrous pericardium forms a flask-shaped bag, the neck of which is closed by its fusion with the external coats of the great vessels, while its base is attached to the central tendon and to the muscular fibers of the left side of the diaphragm . It is also attached to the posterior surface of the sternum by the  superior  and  inferior sternopericardiac ligaments;  the upper passing to the manubrium , and the lower to the xiphoid process .  The vessels receiving fibrous prolongations from this membrane are: aorta , superior vena cava, right and left pulmonary arteries the four pulmonary veins. The inferior vena cava enters the pericardium through the central tendon of the diaphragm, and receives no covering from the fibrous layer.

6. Serous Pericardium: The serous pericardium, in turn, is divided into two layers: - the   parietal pericardium , which is fused to and inseparable from the fibrous pericardium, - the   visceral pericardium , which is part of the  epicardium ; covers the heart and the great vessels and lines the fibrous pericardium.  It is invaginated by the heart In between the parietal and visceral pericardial layers there is a potential space called the pericardial cavity. It is normally lubricated by a film of pericardial fluid , which protects the heart from any kind of external jerk or shock.

7. BLOOD SUPPLY: Internal mammary a. Descending thoracic aorta.     NERVE SUPPLY: Vagus n. Phrenic n. Sympathetic trunks.  

8. FUNCTIONS: Fixes heart in mediastinum and limits its motion Protection from infections coming from other organs (such as lungs) Prevents excessive dilation of heart in cases of acute volume overload Lubrication

9. ANATOMICAL RELATIONS: Surrounds heart and bases of pulmonary artery and aorta. Deep to  sternum and anterior chest wall. The right  phrenic nerve passes to the right of the pericardium. The left  phrenic nerve passes over the pericardium of the left ventricle. Pericardial arteries supply blood to the dorsal portion of the pericardium.

10. APPLIED ANATOMY: Pericarditis  resulting in pericardial friction rub. Pericardial effusion which may lead to cardiac tamponade . Cardiac Tamponade  as a primary pathology following traumatic injury. Pericardial Sinus.