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Anatomy of Pericardium
and Heart








  • Pericardium: The membranous sac filled with serous fluid that encloses the heart and the roots of the aorta and other large blood vessels.

    • A superficial fibrous pericardium.

    • A deep two-layer serous pericardium:

      • The parietal layer lines the internal surface of the fibrous pericardium

      • The visceral layer or epicardium lines the surface of the heart

      • They are separated by the fluid-filled pericardial cavity.

  • Fibrous Pericardium

  • It is a sac made up of connective tissue fully surrounding the heart with out being attached to it

  • It is roughly conical in shape

  • It is superiorly connected with tunica adventitia of great vessels

  • Inferiorly it is connected with central tendon of diaphragm

  • Anteriorly it is separated from thoracic wall by lung & pleura, however some portion of it is in direct relation with left half of lower part of body of Sternum and left 4th &5th costal cartilages

  • Posteriorly it is related to esophagus descending thoracic Aorta & posterior part of mediastinal surface of both lungs

  • Serous Pericardium

  • •It is closed sac within fibrous pericardium having Visceral & Parietal layer

  • •The visceral layer of serous pericardium (epicardium) covers the surface of the heart

  • •It also reflects onto the great vessels

  • •From around the great vessels, the serous pericardium reflects to line the internal aspect of the fibrous pericardium as the parietal

  • layer of serous pericardium

  • Transverse Sinus

  • The transverse sinus is bounded anteriorly by the serous pericardium covering the posterior aspect of the pulmonary trunk and aorta, and posteriorly by the visceral pericardium covering the atria

  • • The transverse pericardial sinus is especially important to cardiac surgeons.

  • • After the pericardial sac has been opened anteriorly, a finger can be passed through the transverse pericardial sinus posterior to the aorta and pulmonary trunk.

  • • By passing a surgical clamp or placing a ligature around these vessels, inserting the tubes of a coronary bypass machine, and then tightening the ligature, surgeons can stop or divert the circulation of blood in these large arteries while performing cardiac surgery.

  • Oblique Sinus

  • The oblique sinus is bounded

  • a. anteriorly by the visceral layer of serous pericardium covering the left

  • atrium

  • b. posteriorly by the parietal layer of serous pericardium lining the fibrous pericardium,

  • c. superiorly and laterally by the reflection of serous pericardium around the four pulmonary veins and the superior and inferior venae cavae

  • Cardiac tamponade

  • • Cardiac tamponade (heart compression) is due to

  • critically increased volume of fluid outside the heart but inside the pericardial cavity; e.g., due to stab wounds or from perforation of a weakened area of the heart muscle after heart attack (hemopericardium).

  • The Heart.
    Position & External Features


  • The heart is located directly on top of the diaphragm behind the sternum.

  • • It is positioned in the middle mediastinum, between the left and right lungs.

  • Structure of the

  • Structure of the Heart:

• The heart is a myocardial muscular pump consisting of four chambers, two auricles, four valves and a muscular septum all enclosed within a fluid filled sac, the pericardium

  • Position:

  • Right border consists entirely of the right atrium.

  • Inferior border is made up mostly of right ventricle with a small portion of left ventricle.

  • Left border is mostly left ventricle, auricle of left atrium forming uppermost part.

  • Anterior or sternocostal surface:

    • Consists of right atrium ,

    • vertical atrioventricular groove,

    • Right ventricle with a narrow strip of left ventricle.

  • Inferior or Diaphragmatic surface consists:

  • Right atrium receiving inferior vena cava, Anteroposterior atrioventricular groove

  • The posterior surface (or base) consists of:

    • Left atrium, receiving the four pulmonary veins.

  •  Position varies a little between systole and diastole.

  • Roots of great vessels fix it, but the ventricles are free to move within the pericardium.

  • In full inspiration, the apex of the heart descends more than the relatively fixed base, and heart occupies somewhat more vertical position.

  • In full expiration, the ascent of the diaphgram forces the heart into more horizontal position.

Heart Wall:

Epicardium – visceral layer of the serous pericardium.

Myocardium – cardiac muscle layer forming the bulk of the heart.

Fibrous skeleton of the heart – crisscrossing, interlacing layer of connective tissue.

Endocardium – endothelial layer of the inner myocardial surface

  • External Heart: Major Vessels of the Heart (Anterior View):

  • Vessels returning blood to the heart include:

    • Superior and inferior venae cavae.

    • Right and left pulmonary veins.

  • Vessels conveying blood away from the heart include:

    • Pulmonary trunk, which splits into right and left pulmonary arteries.

    • Ascending aorta (three branches) – brachiocephalic, left common carotid, and subclavian arteries.

  • Vessels that Supply/Drain the Heart (Anterior View):

  • Arteries right and left coronary (in atrioventricular groove), marginal, circumflex, and anterior interventricular arteries.

  • Veinssmall cardiac, anterior cardiac and great cardiac veins.

  • Major Vessels of the Heart (Posterior View) 

  • Vessels returning blood to the heart include:

    • Right and left pulmonary veins

    • Superior and inferior venae cavae

  • Vessels conveying blood away from the heart include:

    • Aorta

    • Right and left pulmonary arteries.

  • Vessels that Supply/Drain the Heart (Posterior View):

  • Arteries – right coronary artery (in atrioventricular groove) and the posterior interventricular artery (in interventricular groove)

  • Veins great cardiac vein, posterior vein to left ventricle, coronary sinus, and middle cardiac vein.

  • Atria of the Heart:

  • Atria are receiving chambers of the heart.

  • • Each atrium has a protruding auricle.

  • Pectinate muscles mark atrial walls

  • • Blood enters right atria from superior and inferior venae cavae and coronary sinus.

  • • Blood enters left atria from pulmonary veins.

  • Ventricles of

  • Ventricles of the Heart:

  • Ventricles are the discharging chambers of the heart.

  • • Papillary muscles and trabeculae carneae muscles mark ventricular walls.

  • • Right ventricle pumps blood into the pulmonary trunk.

  • • Left ventricle pumps blood into the aorta.

  • Pathway

  • Pathway of Blood Through the Heart and Lungs:

Right atrium à tricuspid valve à right ventricle.

• Right ventricle àpulmonary semilunar valve à pulmonary arteriesà lungs.

• Lungs à pulmonary veins à left atrium.

• Left atrium à bicuspid valve à left ventricle.

• Left ventricleà aortic semilunar valve à aorta.

  • Aortaà systemic circulation.

  • Coronary Circulation:

  • Coronary circulation is the functional blood supply to the heart muscle itself

  • • Collateral routes ensure blood delivery to heart even if major vessels are occluded

  • Heart Valves:

  • Ensure unidirectional blood flow through heart.

  • • Atrioventricular (AV) valves lie between atria and ventricles.

  • • AV valves prevent backflow into atria when ventricles contract.

  • • Chordae tendineae anchor AV valves to papillary muscles

Heart Valves:

Aortic semilunar valve lies between left ventricle and aorta.

Pulmonary semilunar valve lies between right ventricle and pulmonary trunk.

Semilunar valves prevent backflow of blood into ventricles

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