pericaduim anatomy pre - clinical (MBBS)

Anatomy of pericardium for pre-clinical.

1. The pericardium

2. Pericardium: ( Peri -around, Cardium -heart) The pericardium is a fibro-serous sac that encloses the heart and the roots of the great vessels. Its function is: 1) to restrict excessive movements of the heart. serve as a lubricated container to the heart. Acts as shock absorber with the help of the fluid filled sac. The pericardium lies within the middle mediastinum, posterior to the body of the sternum (2 – 6 th costal cartilages) and anterior to the (5 th – 8th thoracic vertebrae).

3. FIBROUS PERICARDIUM: The fibrous pericardium is a sac made of tough connective tissue It is roughly conical and clothes the heart. Attachments: S uperiorly, 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.

4. Anteriorly, it is attached to the posterior surface of the sternum by superior and inferior sternopericardial ligaments . The pericardium is securely anchored by these attachments and maintains the general thoracic position of the heart, serving as the cardiac seat belt’.

5. Relations Anteriorly: Seperated from the thoracic wall by the lungs and the pleural coverings. But, in a small area behind the lower left half of the body of the sternum and the sternal ends of the left 4 th and 5 th costal cartilages , the pericardium is in direct contact with the thoracic wall. the lower end of the thymus.

6. Inferiorly: the pericardium is seperated from the liver and the fundus of stomach by the diaphragm.

7. 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: Mediastinal Pleura. The phrenic nerve with its accompaning vessels, descends between the mediastinal pleura and the fibrous pericardium on either side.

8. SEROSAL PERICARDIUM : The serous pericardium lines the fibrous pericardium and coats the heart. It is divided into parietal and visceral layers. The parietal layer lines the fibrous pericardium and is reflected around the roots of the great vessels to become continuous with the visceral layer of serous pericardium that closely covers the heart .

9. The visceral layer is closely applied to the heart and is often called the epicardium . The slitlike space between the parietal and visceral layers is referred to as the pericardial cavity . Normally, the cavity contains a small amount of tissue fluid (about 50 mL), the pericardial fluid, which acts as a lubricant to facilitate movements of the heart.

10. Pericardial Sinuses On the posterior surface of the heart, the reflection of the serous pericardium around the large veins forms a recess called 1. oblique sinus . 2. transverse sinus , which is a short passage that lies between the reflection of serous pericardium around the aorta and pulmonary trunk ( post.surface of heart). The pericardial sinuses formed as a consequence of the way the heart bends during development. They have no clinical significance.

11. Vascular supply: 1. internal thoracic. 2. musculophrenic arteries. 3. descending thoracic aorta. The veins are tributaries of the azygous system.

12. Innervation: phrenic nerves : ( fibrous pericardium and the parietal layer of the serous pericardium). 2) branches of the sympathetic trunks and the vagus nerves (visceral layer of the serous pericardium) .

13. Clinical Notes Pericarditis: (inflammation of the serous pericardium). pericardial fluid may accumulate excessively, which can compress the atria and interfere with the filling of the heart during diastole. This compression of the heart is called cardiac tamponade . Cardiac tamponade can also occur secondary to stab or gunshot wounds when the chambers of the heart have been penetrated. The blood escapes into the pericardial cavity and can restrict the filling of the heart .

14. in acute pericarditis : Roughening of the visceral and parietal layers of serous pericardium by inflammatory exudate produces pericardial friction rub, which can be felt on palpation and heard through a stethoscope . Pericardial fluid can be aspirated from the pericardial cavity by process called paracentesis . The needle can be introduced to the left of the xiphoid process in an upward and backward direction at an angle of 45° to the skin. When paracentesis is performed at this site, the pleura and lung are not damaged because of the presence of the cardiac notch in this area .

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