PERICARDIUMPERICARDIUM

Dr.GurudasanDr.Gurudasan28.04.1428.04.14

INTRODUCTIONINTRODUCTION

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Pericardium is a triple- layered fibro-serous sac that encloses the heart and roots of great vessels.It consists of fibrous and serous pericardium (Parietal and visceral layers).

DEVELOPMENT OF DEVELOPMENT OF PERICARDIUMPERICARDIUM

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Pericardial cavity develops from intraembryonic coelom. cardiac tube invaginates the pericardial sac from dorsal aspect. The splanchnopleuric mesoderm gives rise to myocardium and epicardium (Visceral pericardim). The somatopleuric mesoderm gives rise to parietal pericardium. Fibrous pericardium is developed from septum transversum.

FIBROUS PERICARDIUMFIBROUS PERICARDIUM The fibrous pericardium

is a sac made of tough connective tissue, completely surrounding the heart without being attached to it.

Apex of fibrous pericardium is continuous with adventitia of great vessels at the level of sternal angle & also as pretracheal fascia.

Base of fibrous pericardium blends with diaphragm.

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Fibrous pericardium

Apex of Fibrous pericardium

Base of fibrous pericardium

Relations:Relations:

Anteriorly –Anteriorly – superior and inferior sternopericardial ligaments, thymus

Posteriorly –Posteriorly – Principle bronchi, oesophagus, descending thoracic aorta

Laterally – Laterally – Mediastinal pleura, phrenic nerve

Inferiorly –Inferiorly – Diaphragm

Cardiac seat belt: Cardiac seat belt: Pericardium is securely anchored by these connections and maintains the general thoracic position of the heart, serving as the ‘cardiac seat belt'.

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Oesophagus

Thymus

Heart with fibrouspericardium

Mediastinal pleura

Principle bronchus

DescendingThoracicaorta

FUNCTIONS OF FIBROUS FUNCTIONS OF FIBROUS PERICARDIUMPERICARDIUM

It resembles a bag that rests on and attaches to the

diaphragm; its open end is fused to the connective

tissues of the blood vessels entering and leaving the

heart. The fibrous pericardium prevents overstretching

of the heart, provides protection, and anchors the heart

in the mediastinum.

In the life saving procedure external cardiac massage,

the heart is squeezed inside the firm fibrous pericardium

between the vertebral column and resilient sternum and

costal cartilages by applying rhythmic pressure.

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SEROUS PERICARDIUMSEROUS PERICARDIUM The serosal

pericardium is a closed sac within the fibrous pericardium, and has a visceral and a parietal layer.

The visceral layer (epicardium) covers the heart and great vessels and is reflected into the parietal layer, which lines the internal surface of the fibrous pericardium.

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Along the lines of pericardial reflection there are two pericardial sinusesAlong the lines of pericardial reflection there are two pericardial sinusesnamely transverse and oblique.namely transverse and oblique.

PERICARDIAL SINUSESPERICARDIAL SINUSESTransverse sinus:Transverse sinus:

It lies between the aorta and pulmonary trunk in front and the atria and pulmonary veins behind.

Oblique sinus:Oblique sinus:It lies between the pericardial reflection from IVC and Rt.Pulm veins on right side and Lt.pulm veins on left side.

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Transverse sinus

Oblique sinus

Pulm. arteryAorta

SVC

IVC

Pulm.Veins

BOUNDARIES:BOUNDARIES:

Transverse sinus:Transverse sinus:

Ant: Ant: Visceral pericardium covering ascending aorta and pulm.trunk.

Post: Post: Visceral pericardium covering left atrium.

It is open on either side

Oblique sinus:Oblique sinus:

Ant: Ant: Visceral pericardium covering left atrium.

Right: Right: Pericardial reflections of IVC and Pul.veins

Left: Left: Pericardial reflections of Lt.Pul veins

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FUNCTIONS OF FUNCTIONS OF SINUSESSINUSESTransverse sinus provides space

during cardiac surgery to clamp the ascending aorta and pulmonary trunk in order to insert tubes of heart lung machines in these vessels.

Oblique sinus acts as a bursa for the left atrium to expand during filling.

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BLOOD SUPPLYBLOOD SUPPLY Fibrous pericardium and Fibrous pericardium and

parietal layer of serous parietal layer of serous pericardium:pericardium:Pericardial branches of internal thoracic artery and of desceding thoracic aorta provide arterial blood.Pericardial veins drain into the azygos and hemiazygos veins.

Visceral pericardium:Visceral pericardium:Supplied by coronary arteries and drains into coronary sinus.

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NERVE SUPPLYNERVE SUPPLY phrenic nerve innervate the fibrous

pericardium as well as the parietal layer of serous pericardium. These fibers generally carry the sensation of pain. Parasympathetic fibers arise as branches of the Vagus nerve in the neck and thorax and innervate the visceral layer of serous pericardium.

Sympathetic fibers from the cervical and upper thoracic sympathetic chain of ganglia and innervate the visceral layer of serous pericardium just like the sympathetic fibers.

 

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CLINICAL ANATOMYCLINICAL ANATOMYPericarditis:

Inflammation of serous pericardium is called pericarditis.

- May be due to bacterial or viral infection, RHD.

- Pain is referred to precordium or epigastrium.

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CLINICAL ANATOMYCLINICAL ANATOMYPericardial pain is typically a sharp severe

substernal pain. It may be exacerbated by lying back or on the left side and relieved by leaning forward. It occasionally radiates to the upper border of trapezius.

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CLINICAL ANATOMYCLINICAL ANATOMY

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Cardiac tamponade is external compression of the heart usually causedby accumulation of fluid in the pericardial space. This causes compression of the right atrium and reduces venous return, which reduces cardiac output. It results in increased heart rate and increased venous pressure.

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Excessive fluid accumulation within the parietal and visceral layer of Serous pericardium lead to pericardial effusion. It is usually removed by two routes of pericardiocentesis:I) Parasternal route: Needle is inserted in the left 4th or 5th ICS close to sternum. Since line of pleural reflection deviates in left side, pleura will be spared.II) Subcostal route: needle is introduced at left costoxiphoid angle (45°).

Globular heart shadowIn pericardial effusion

PERICARDIOCENTESISPERICARDIOCENTESIS::

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