Pericardium

• Pericardium


  Fibroserous membrane enclosing the heart and roots of the great vessels

  
• Pericardium


  • Situated in the middle mediastinum
  • Restricts excessive movements of heart
  • Lubricated container in which different parts of the heart can contract

  
• Parts of pericardium


  • Fibrous pericardium
  • Serous pericardium
  • Visceral pericardium
  • Parietal pericardium

  
• Fibrous pericardium


  • Outer most layer, thick, fibrous covering, conical shaped – has apex and base
  • Inferiorly (base) attached to the central tendon of diaphragm
  • Apex is pierced by the ascending aorta, the pulmonary trunk and the superior vena cava
  • Right aspect of the base is pierced by the inferior vena cava
  • Posterior surface is pierced by the four pulmonary veins
  • Anterior surface is attached to the sternum by the sternopericardial ligaments
  • Inner surface is lined by parietal layer of serous pericardium
  • Fuses with the tunica adventitia of blood vessels piercing it

  
• Serous pericardium


  Has 2 layers: Visceral pericardium (inner layer) and Parietal pericardium (outer layer)

  
• Visceral pericardium


  Inner layer of serous pericardium, closely lines the heart, lines the part of the great blood vessels present in the fibrous pericardium, continuous with the parietal pericardium

  
• Parietal pericardium


  Outer layer of serous pericardium, lines the inner surface of fibrous pericardium

  
• Pericardial cavity


  Cavity which separates the 2 layers of serous pericardium, contains pericardial fluid (15 -50 ml), fluid acts as a lubricant and facilitate the movements of heart

  
• Transverse pericardial sinus


  Located behind the ascending aorta and pulmonary trunk, in front of right atrium and superior vena cava, remnant of an aperture in the dorsal mesocardium of the embryonic heart, separating the venous and arterial ends of the heart tube, allows a surgeon to isolate the pulmonary trunk and ascending aorta and apply a temporary ligature or clamp
• Oblique pericardial sinus


  Recess of pericardial cavity situated behind the left atrium, situated between the pulmonary veins and inferior vena cava
• Blood supply and nerve supply of pericardium

  • Fibrous and parietal pericardium: Musculophrenic artery and vein, Pericardiophrenic artery and vein, Phrenic nerve
  • Visceral pericardium: Right and left coronary arteries, Veins end in coronary sinus, Cardiac plexus of nerves
• Development of pericardium


  • Fibrous and parietal pericardium – somatopleuric layer of intraembryonic mesoderm
  • Visceral pericardium – splanchnopleuric layer of intraembryonic mesoderm

  
• Applied anatomy of pericardium


  • Pericarditis – Inflammation of the pericardium
  • Pericardial rub – Inflammation of pericardium make the serous pericardium rough, friction of the roughened surfaces may sound like the rustle of silk
  • Pericardial effusion - passage of fluid from pericardial capillaries into the pericardial cavity, or an accumulation of pus
  • Hemopericardium – blood in the pericardial cavity
  • Pneumopericardium – air or gas in the pericardial cavity
  • Cardiac tamponade - heart compression

  
• Pericardiocentesis


  Drainage of fluid from the pericardial cavity, to remove the excess fluid, a wide-bore needle may be inserted through the left 5th or 6th intercostal space near the sternum or via the infrasternal angle by passing the needle superoposteriorly
• Main function of the pericardium?

  Prevents over filling and over expansion of the heart
• What makes up the blood supply for the fibrous and parietal pericardium?

  Pericardiophrenic arteries, Internal thoracic, Musculophrenic arteries, the descending thoracic aorta, Veins that drain into corresponding veins
• The phrenic nerves are sensitive to pain because?


  They are sensitive to pain because they contain pain sensations which are referred to the skin( C3- C5 dermatomes) of the ipsilateral supraclavicular region
• The visceral pericardium(epicardium) is supplied by which nerves?

  Autonomic nerves which are not sensitive to pain
• What are the boundaries of the transverse sinus?

  Anteriorly: Ascending Aorta and Pulmonary trunk

  Posteriorly: Left atrium and superior vena cava

  On each side : pericardial cavity
• What are the boundaries of the oblique sinus?


  Anteriorly : left atrium

  Posteriorly : esophagus and parietal pericardium
• What is systemic circulation?

  The circulation of blood from the heart to the rest of the body and back to the heart.
• What is pulmonary circulation?

  Circulation of blood between the heart and the lungs.
• What is the process of systemic circulation?

  Left ventricle > Aortic Valve > Aorta > Oxygenated blood to all tissues except lungs >venous blood collected > superior and inferior vena cava> right atrium
• What is the process of pulmonary circulation?

  right ventricle> pulmonary valve> pulmonary trunk/artery> lung> deoxygenated blood gets oxygenated> 4 pulmonary veins>left atrium
• What are the tributaries of the right atrium?

  Superior vena cava, inferior vena cava, coronary sinus, anterior cardiac veins and venae cordis minimae
• what is the tricuspid orifice guarded by?

  Tricuspid valve
• What are the internal features of the right atrium?


  smooth posterior part and rough anterior part
• what tributaries flow into the smooth posterior part of the right atrium?

  superior vena cava, inferior vena cava, coronary sinus and venae cordis minimae
• What is in the rough anterior part of the atrium?


  Has a series of transverse muscular ridges called musculi pectinati
• What are some features of the right atrium?


  Receives venous blood from the body, Pushes blood to the right ventricle through the tricuspid valve, forms the right border, part of sternocostal and small part of the base of the heart and is enlarged in tricuspid stenosis
• What are some features of the left atrium?


  Receives oxygenated blood from the lungs, pushes blood to left ventricle through bicuspid valve, forms major part of the base of the heart, is enlarged during mitral stenosis
• What are the features of the right ventricle?


  thinner walls, thinner than left ventricle, pushes blood only to lungs, contains 3 small papillary muscles, cavity is crescentic, contains deoxygenated blood, forms 2/3 sternocostal and 1/3 diaphragmatic surfaces