Heart Anatomy (PDF)

Tishk International University Dentistry Faculty Basic Science Department TOPIC: Anatomy of the heart Instructor: Dr. Paiman Jamal  Facts, location, & orientation Oblique orientation Apex points (down and left) – 5th intercostal space Base is superior near origins of great...

Tishk International University Dentistry Faculty Basic Science Department TOPIC: Anatomy of the heart Instructor: Dr. Paiman Jamal  Facts, location, & orientation Oblique orientation Apex points (down and left) – 5th intercostal space Base is superior near origins of great vessels – 2nd intercostal space 2/3 lies left of the midline For the most part – Anterior/inferior aspect of the heart right atrium/ventricle – Posterior/superior aspect left atrium/ventricle  Mediastinum Mediastinum Superior Inferior Anterior Middle Posterior Heart  The mediastinum is divided, for descriptive purposes, to superior and inferior mediastina by an imaginary plane passing horizontally through the sternal angle. The inferior mediastinum, in turn, is divided into anterior mediastinum(anterior to pericardium), posterior mediastinum (posterior to pericardium) and middle mediastinum (occupied by heart and pericardium)  Fibrous pericardium Is the strong fibrous part of the sac. It is the outermost single layer. Inferiorly it is attached firmly to the diaphragm. Superiorly it fuses with the outer coat of the great blood vessels that pass through it. ( namely the aorta, pulmonary trunk, superior vena cava, inferior vena cava and pulmonary veins.)  Serous pericardium Is a double layer serous membrane. Parietal layer lines the fibrous pericardium, and the visceral layer closely covers the heart. Between these to layers is the pericardial cavity which contains little amount of fluid (pericardial fluid) that acts as a lubricant to facilitate movements of the heart.  Structure of the Heart – Coverings Fibrous pericardium Serous pericardium – Parietal pericardium – Visceral pericardium  Sulci of the heart Coronary sulcus – Atrioventricular sulcus Circumvents the heart Interventricular sulcus – Anterior – Posterior  Great vessels Aorta – From left ventricle Pulmonary trunk – Originates anterior to the aorta from right ventricle Superior Vena Cava Inferior Vena Cava – Both empty into right atrium  Aorta Ascending aorta – Right and left aortic sinuses Arch of aorta – Begins/ends at T4/T5 or sternal angle level – Main branches are: – Brachiocephalic a. – Left common carotid a. – Left subclavian a. Thoracic aorta – Lies anterior to trachea  Ligamentum arteriosum Remnant of embryonic ductus arteriosus Attaches aortic arch superiorly to pulmonary trunk/left pulmonary artery inferiorly Identification point for Left recurrent laryngeal nerve  Heart Features Chambers Valves –Right atrium – Leaflet valves Tricuspid –Right ventricle Bicuspid –Left atrium (mitral) –Left ventricle – Cusped (semilunar) valves Aortic Pulmonic  Right atrium Auricle (ear) Pectinate muscles (rough) Sinus venarum (smooth) – Crista terminalis Division between rough to smooth Openings (ostia) – SVC/IVC/Coronary sinus Fossa ovalis – Foramen ovale in fetus – Limbus  Right atrium “valves” Superior vena cava – No valve Inferior vena cava – Eustachian valve Incompetent in adult, directs IVC blood though Foramen ovale in fetus Coronary Sinus – Thebesian valve Prevents backflow into coronary sinus during atrial systole  Left atrium Ostia of 4 pulmonary veins – 2 superior – 2 inferior Auricle  Right ventricle Most anterior aspect of heart Tricuspid valve (RA-RV) – Anterior/Posterior/Septal cusps (leafs) Papillary muscles – Connected to cusps via Chordae tendinae – Contract to prevent Tricuspid valve regurgitation – Named same as cusps Trabeculae carnae Moderator band  Left ventricle Trabeculae carnae Bicuspid (mitral) valve – Anterior/Posterior cusps Papillary muscles – Chordae tendinae Usually a greater number than the right, due to the increased pressures and strength necessary to prevent regurgutation  Pulmonic valve From RV to pulmonary trunk Lies just anterior to aortic valve 3 semilunar cusps – Anterior – Right – Left  Aortic valve Posterior to pulmonic valve 3 cusps – Posterior (non-coronary) cusp – Right – Left Just superior to right and left cusps are the openings of the right and left coronary arteries, respectively  Heart Valves Tricuspid valve – RA – RV Bicuspid valve – LA – LV “Mitral valve” Aortic valve – LV – aorta Pulmonic valve – RV – pulmonary trunk Conducting system Right coronary blood supply Right coronary artery – Originates from ostia in right aortic sinus Superior to right aortic cusp – Travels in right coronary (AV) sulcus – Branches Right marginal arteries (acute marginal aa) Posterior interventricular a. (in post. IV sulcus) Sinoatrial nodal a. Atrioventricular nodal a. Left coronary blood supply Left coronary artery – Originates from ostia in left aortic sinus Superior to left aortic cusp – Branches Left anterior descending (LAD) or anterior interventricular a. (lies in anterior IV sulcus) – Septal branches. – Diagonal branches Left marginal aa. (Obtuse marginal aa.) Left circumflex a.  Dominance Defined by branch that gives rise to posterior interventricular a. – Right (80%) From right coronary a. – Left (15%) From left circumflex a. – Co-dominance (5%)  Venous drainage of the heart Coronary sinus – Lies in coronary (AV) sulcus on posterior – Opens directly to right atrium – All venous drainage of the heart eventually flows here Great cardiac vein – With LAD in anterior IV sulcus Left marginal vein Middle cardiac vein – With posterior interventricular a. Small cardiac vein – With right coronary a. Right marginal vein Oblique vein (LA) Posterior vein of the left ventricle Inside the Heart…a review Frontal Section of the Heart Chambers and Valves