Pericardium & Heart PDF

Pericardium & Heart 2  Pericardium Layers: 1) Outer fibrous 2) Inner serous: formed of:  Parietal layer: lining the fibrous pericardium  Visceral layer:: covering the heart  Pericardial space: between visceral & pari...

Pericardium & Heart 2  Pericardium Layers: 1) Outer fibrous 2) Inner serous: formed of:  Parietal layer: lining the fibrous pericardium  Visceral layer:: covering the heart  Pericardial space: between visceral & parietal layers Parts:  Apex: surrounds the great vessels  Base: attached to central tendon of diaphragm  Surfaces:  Anterior: attached to sternum by upper & lower sterno-pericardial ligaments  Posterior: related to oblique sinus, esophagus, aorta, middle 4 thoracic vertebrae  Lateral: related to the phrenic nerve & pericardiophrenic vessels N.B: Bare area of heart: area not covered by lung or pleura It lies opposite 4th &5th ICS. It is the site for pericardio-centsis Nerve supply:  Fibrous & Parietal pericardium: painful by phrenic nerves (C3, 4, 5), so pericarditis is referred to shoulder  Visceral pericardium: painless "it receives autonomic nerve supply" Arterial supply:  Fibrous & Parietal Pericardium: supplied by pericardiophrenic, musculophrenic & Descending aorta  Visceral Pericardium: supplied by coronary arteries DR.Hendawy “CVS” 3 Pericardial sinuses: 1) Oblique sinus :  Pericardial recess behind left atrium  Related to esophagus & descending aorta  It is bounded:  Anteriorly by left atrium  Posteriorly by esophagus, descending aorta  Superiorly: reflection of visceral pericardium to become parietal  Inferiorly by opening in pericardium  On the left side by 2 Left pulmonary veins  On the right side by 2 Right pulmonary veins 2) Transverse sinus:  Transverse passage connect right & left sides of the pericardial cavity  Formed by degeneration of mesoderm between heart tube & esophagus  It is bounded:  Anteriorly by ascending aorta &pulmonary trunk  Posteriorly by superior vena cava  Inferiorly by both atria mainly the left  Superiorly by right pulmonary artery N.B: the left atrium separates the transverse from the oblique sinuses. DR.Hendawy “CVS” 4  Heart External features  Site: In middle mediastinum  Size: closed fist  Shape: Conical with the axis directed downward, forward & to the left  Parts: o Apex: Formed by Left ventricle Direction Downward, forward & to Left Surface anatomy: left 5th intercostal space, 3.5 inches (9 cm) from middle line “at midclavicular line” o Base Formed by Both atria (mainly Left) Relation: Oblique sinus, descending aorta, Esophagus, middle 4 thoracic vertebrae o Surfaces:  Anterior surface (Sterno-costal): Formed by: all chambers (mainly Right ventricle) Relation: Sternum, 3-6 Costal cartilages & Sternocostalis muscle  Lateral surfaces Formed by:  Right surface formed by Right Atrium  Left surface formed by Left auricle & ventricle Relation: Phrenic nerve & Pericardio-phrenic vessels DR.Hendawy “CVS” 5   Inferior surface (Diaphragmatic) Formed by: Both ventricles (mainly Left) Related to: central tendon of diaphragm o Borders:  Superior border: formed by both aria mainly Left atrium  Right border: formed by Right atrium only  Inferior border: formed by both ventricles mainly Right ventricle.  Left border: formed by Left auricle & Left ventricle “mainly” DR.Hendawy “CVS” 6  Surface anatomy of heart Apex: A point on the left 5th intercostal space, 3.5 inches (9 cm) from the middle line “at the mid-clavicular line” Superior border:  From “lower border of left 2nd costal cartilage, 1.5 cm from sternum”  To “upper border of right 3rd costal cartilage, 1.5 cm from sternum”. Right border:  From “upper border of right 3rd costal cartilage, 1.5 cm from sternum”  To “right 6th costal cartilage,2 cm from sternum” Inferior border:  From “right 6th costal cartilage, 2 cm from sternum”  To “left 5th intercostal space, 3.5 inches from midline” Left border:  From “left 5th intercostal space, 3.5 inches from midline”  To “lower border of left 2nd costal cartilage, 1.5 cm from sternum” Coronary groove:  From “Left 3rd costal cartilage”  To “Right 6th costal cartilage” DR.Hendawy “CVS” 7  Heart valves Pulmonary valve  Site: between right ventricle & pulmonary trunk  Size: 3 cm  Surface anatomy: Behind Left sternal margin opposite 3rd costal cartilage  Site of auscultation: Left 2nd intercostal space  Cusps: 3 Semilunar cusps “1 Anterior, 2 posterior” Aortic valve  Site: between Left ventricle & ascending aorta  Size: 2.5 cm  Surface anatomy: Behind Left sternal margin opposite 3rd inter-costal space  Site of auscultation: right 2nd intercostal space  Cusps: 3 Semilunar cusps “1 posterior, 2 Anterior” Mitral valve  Site: between Left ventricle & left atrium  Size: admit 2 fingers  Surface anatomy: Behind Left sternal margin opposite 4th costal cartilage  Site of auscultation: left 5th intercostal space at midclavicular line  Cusps: 2 triangular cusps “posterior, anterior” Tricuspid valve  Site: between right ventricle & right atrium  Size: admit 3 fingers  Surface anatomy: Behind midline opposite 4th inter-costal space  Site of auscultation: medial end of left 5th intercostal space  Cusps: 3 triangular cusps “septal, posterior, anterior DR.Hendawy “CVS” 8  Arterial supply of heart Right coronary Origin: Right aortic sinus of ascending aorta Course: it passes between pulmonary trunk & right auricle then between right Atrium &ventricle End: Anastomose with circumflex branch of Left coronary artery Branches:  Right Atrium & Right Ventricle  SAN 65% & AVN 80%  Right marginal: to Right Ventricle  Posterior inter-ventricular: “largest branch” supply inferior surface of both ventricles & Posterior 1/3 of inter-ventricular septum DR.Hendawy “CVS” 9  Left coronary Origin: left aortic sinus of ascending aorta Course & termination: it passes between pulmonary trunk & Left auricle till anterior inter-ventricular groove where it gives: o Anterior inter-ventricular: passes in anterior inter-ventricular groove with great cardiac vein o Circumflex: passes between left Atrium & ventricle to anastomose with Right coronary artery Branches: Circumflex: supply:  Left Atrium & left Ventricle  SAN 35% & AVN 20%  Left marginal: to Left Ventricle Anterior inter-ventricular artery: Supply anterior surface of both Ventricles & Anterior 2/3 of interventricular septum N.B: Coronary dominance is defined by which artery gives rise to the posterior inter-ventricular artery. Right dominance occurs in 75% of people while Left dominance: occurs in 10% & codominance occurs in 15% of people. DR.Hendawy “CVS” 10  Venous drainage of heart Vena cordis minimi: open in all chambers of heart Anterior cardiac vein: open into anterior wall of right Atrium Coronary sinus: Site: posterior part of coronary sulcus between Left Atrium & Left Ventricle End: posterior wall of right atrium Tributaries:  Oblique vein of left atrium  Posterior vein of left ventricle  Great cardiac vein: pass with anterior inter-ventricular artery  Middle cardiac vein: pass with posterior inter-ventricular artery  Small cardiac vein: pass with right coronary artery N.B: Anterior interventricular groove contains anterior interventricular artery & great cardiac vein N.B: posterior inter-ventricular groove contains posterior interventricular artery & middle cardiac vein N.B: coronary sulcus contains right coronary artery & small cardiac vein & circumflex artery & coronary sinus DR.Hendawy “CVS” 11  Conduction System of the Heart  Sinoatrial (SA) Node: Found at crista terminalis of right atrium. It acts as the pacemaker of heart  Atrioventricular (AV) node: Located in the lower part of inter-atrial septum  AV bundle “bundle of His”: Extends into membranous part of interventricular septum.  Right branch of AV bundle: pass in moderator band  Left branch of AV bundle: pass in interventricular septum Cardiac plexuses  Superficial cardiac plexus:  Found below aortic arch  Formed of left sympathetic chain & left vagus  Deep cardiac plexus:  Found infront of tracheal bifurcation  Formed of both sympathetic chains & both vagi N.B: pain of myocardial infarction is radiating to the upper medial part of arm as the sensation from the heart is transferred to upper 5 thoracic sympathetic ganglia. The 2nd ganglion is connected with 2nd intercostal nerve through rami communicants then pain is transmitted through intercosto-brachial branch of 2nd ICN to upper medial part of arm DR.Hendawy “CVS” 12  Internal features of heart Right atrium: o Crista terminalis: vertical ridge between SVC & IVC openings corresponds to crista terminalis o Anterior wall: shows Musculi pectinati “Parallel muscular ridges from Crista terminalis” o Posterior wall: receives  Superior vena cava “has no valve” : open at the level of 3rd costal cartilage  Inferior vena cava “has valve” : open at the level of 6th costal cartilage  Coronary sinus “has valve” o Septal wall: marked by fossa ovalis surrounded by annulus ovalis o Openings:  Vena cordis minimi  Anterior wall: receive anterior cardiac veins  Posterior wall receives SVC ,IVC, Coronary sinus openings  Tricuspid valve opening DR.Hendawy “CVS” 13 Left atrium: o No Crista terminalis: o Anterior wall: shows less Musculi pectinati “just in the auricle” o Posterior wall: receives 4 pulmonary veins o Septal wall: shows faint fossa ovalis & annulus ovalis o Openings:  Vena cordis minimi  Posterior wall receives 4 pulmonary veins  Mitral valve opening DR.Hendawy “CVS” 14 Right ventricle : o Outflowing part:  Smooth part “Infundibulum”  Lead to pulmonary trunk o Inflowing part:  Anterior wall is rough due to presence of “Trabeculi carni”  3 Papillary muscles  Anterior “the largest”  Posterior  Septal “the smallest” They prevent tricuspid regurge through their extension from ventricular wall to inferior surface of tricuspid valve by chorda tendinea  Moderator band:  Extend from septal wall to anterior wall  Contain right AV bundle  Prevents over-distension of right ventricle  Thickness: Wall is thin  Lumen is semi-lunar in shape o Openings:  Vena cordia minimi  Pulmonary valve  Tricuspid valve DR.Hendawy “CVS” 15 Left ventricle : o Outflowing part:  Smooth part “vestibule”  Lead to ascending aorta o Inflowing part:  Anterior wall is rough due to presence of “more trabeculi carni”  2 Papillary muscles “anterior, posterior”  Arises from ventricular walls  Attached to ventricular surface of mital valve by chorda tendinea  No Moderator band  Thickness: 3 times thicker than right one  Lumen is circular in shape o Openings:  Vena cordia minimi  Aortic valve  Mitral valve DR.Hendawy “CVS” 16