Heart and Coronary Circulation (Dissection Video) PDF

(002) HEART AND CORONARY CIRCULATION (DISSECTION VIDEO) DR. LESLIE AS...

(002) HEART AND CORONARY CIRCULATION (DISSECTION VIDEO) DR. LESLIE ASUNCION-VIADO| 12/14/20 OUTLINE A. ANTERIOR SURFACE OF THE HEART I. HEART IN SITU 1. Structures: a. Right atrium A. Anterior Surface of the Heart b. Atrioventricular groove B. Inferior (Diaphragmatic) Surface c. Right ventricle d. Anterior interventricular groove of the Heart e. Some part of the Left ventricle II. OPENED HEART f. Some part of the auricular appendage of the Left A. Right Atrium atrium 2. Blood vessels: B. Right Ventricle ARTERY - more elastic and thicker wall C. Left Atrium and Left Ventricle a. Right Coronary Artery - passes through right auricle III. BLOOD VESSLES OF CORONARY and pulmonary trunk b. Right (Acute) Marginal Artery - branch of Right CIRCULATION coronary artery; located at the inferior margin of the heart c. Anterior Interventricular Artery - a.k.a. Left anterior I. HEART IN SITU descending (LAD) artery; located at the anterior interventricular groove VEIN a. Great Cardiac Vein - This accompanies the Anterior Interventricular branch of the Left Coronary Artery b. Small Cardiac Vein Figure I.A Heart in situ 1. Thymus gland 2. Brachiocephalic trunk 3. Superior vena cava 4. Pericardium 5. Phrenic nerve and pericardiacophrenic artery and vein 6. Recurrent laryngeal nerve Figure I.B Anterior surface of the heart 7. Arch of aorta 8. Left brachiocephalic vein  The pericardium has been incised and turned back (23) to display the anterior surface of the heart. The pulmonary trunk (17) leaves the right ventricle (22) in front and to the left of the  The heart lies within the middle mediastinum, encased within a ascending aorta (3), which is overlapped by the auricle (5) of the fibroserous sac called the pericardium. The outer layer of the right atrium (18). The superior vena cava (25) is to the right of pericardium is the fibrous pericardium, a strong, fibrous layer the aorta and still largely covered by pericardium. The anterior that blends with the roots of the great vessels. Serous interventricular branch (2) of the left coronary artery and the pericardium consists of an underlying parietal layer lining the great cardiac vein (7) lie in the interventricular groove between inner aspect of the fibrous pericardium and a visceral layer that the right and left ventricles (22 and 11), and the right coronary reflects onto the heart as the epicardium. artery (19) is in the atrioventricular groove between the right ventricle (22) and right atrium (18). Page 1 of 6 CMED 1A  (002) HEART AND CORONARY CIRCULATION (DISSECTION VIDEO) DR. LESLIE ASUNCION-VIADO| 12/14/20 NOTE: 10. Left ventricle The right border of the heart is formed by the right atrium. 11. Middle cardiac vein and posterior interventricular branch of right The left border is formed mostly by the left ventricle with at the coronary artery in posterior interventricular groove top the uppermost part (infundibulum) of the right ventricle and 12. Posterior vein of left ventricle the tip of the left auricle. 13. Right atrium The inferior border is formed by the right ventricle with a small 14. Right pulmonary artery part of the left ventricle at the apex. 15. Right ventricle The sternocostal surface of the heart is the anterior surface 16. Superior left pulmonary vein formed mainly by the right ventricle with parts of the left ventricle 17. Superior right pulmonary vein and right atrium. 18. Superior vena cava The apex of the heart is formed by the left ventricle. The base of the heart is the posterior surface, formed mainly by Note: the left atrium with a small part of the right atrium. The inferior surface is the diaphragmatic surface, formed by Inferior surface - where the heart rests the two ventricles (mainly the left). Posterior surface - base of the heart (which faces the apex) The heart does not lie on its base; it lies on its diaphragmatic / Anterior interventricular branch of left coronary artery - left inferior surface. anterior descending (LAD) as often used by clinicians. Coronary sinus - located inferior to the left atrium; receives the pulmonary veins. Rudimentary valve - opening of the coronary sinus (In fact, it B. INFERIOR (DIAPHRAGMATIC) SURFACE OF THE should admit the little finger of the owner) HEART 1. Structures: II. OPEN HEART a. Posterior Interventricular groove 2. Blood Vessels: a. Posterior Interventricular Artery - thick wall A. RIGHT ATRIUM b. Middle Cardiac Vein - thin wall 1. Structures: a. Superior vena cava b. Inferior vena cava c. Musculi pectani - rough surfaces inside the Right atrium d. Crista terminalis - border between rough and smooth part of the Right atrium e. Fossa ovalis f. Limbus Figure I.C Inferior surface of the heart 1. Auricle of left atrium 2. Coronary sinus in posterior atrioventricular groove 3. Great cardiac vein and anterior interventricular branch of left Figure II.A Right Atrium (opened) coronary artery 4. Great cardiac vein and circumflex branch of left coronary artery 5. Inferior left pulmonary vein The anterior wall has been incised near its left margin and 6. Inferior right pulmonary vein reflected to the right, showing on its internal surface the vertical 7. Inferior vena cava crista terminalis (2) and horizontal pectinate muscles (7). The fossa ovalis (3) is on the interatrial septum, and the opening of 8. Left atrium the coronary sinus (6) is to the left of the inferior vena caval 9. Left pulmonary artery opening (4). Page 2 of 6 CMED 1A  (002) HEART AND CORONARY CIRCULATION (DISSECTION VIDEO) DR. LESLIE ASUNCION-VIADO| 12/14/20 NOTE: septum (13) to the anterior papillary muscle (2), was formerly The smooth portion of the right atrium is known as the sinus known as the moderator band. The chordae tendineae (5) venarum because it develops from the embryonic sinus connect the cusps of the tricuspid valve to the papillary muscles. venosus and receives blood from the superior and inferior venae cavae and coronary sinus. It is separated from the more NOTE: muscular portion of the atrium proper by a line, the crista Chordae tendineae connect papillary muscles to the cusps of terminalis. the tricuspid, or right atrioventricular, valve. During contraction of The fossa ovalis is the adult representation of the embryonic the right ventricle, the chordae tendineae prevent the valve foramen ovale. cusps from everting into the right atrium. Although the right atrium is slightly larger than the left atrium, The septomarginal trabecula (moderator band) of the it has thinner walls because the pressure on the right side of trabeculae carneae connects the interventricular septum to the the heart is normally lower than that on the left side. base of the anterior papillary muscle. Contraction of this band of The auricle is a pouch-like appendage of the atrium but is muscle prevents overdistention of the ventricle. functionally identical to the rest of the atrium. The interventricular septum is largely muscular, but its The fossa ovalis forms part of the interatrial septum, and is part superior aspect contains a small membranous portion that is a of the embryonic primary septum. common site for ventricular septal defects. The limbus, which forms the margin of the fossa ovalis, represents the lower margin of the embryonic secondary septum. Before the primary and secondary septa fuse (at birth), C. LEFT ATRIUM AND LEFT VENTRICLE the gap between them forms the foramen ovale. LEFT ATRIUM The sinuatrial node (SA node) is embedded in the anterior wall - Most parts are smooth (surfaces) of the atrium at the upper end of the crista terminalis, just below - Receives pulmonary veins the opening of the superior vena cava. The atrioventricular node (AV node) is embedded in the - Left auricle: rough part of Left atrium; it opens by the Left atrioventricular orifice, guarded by Mitral (bicuspid) valve, interatrial septum, just above and to the left of the opening of the coronary sinus. connects into the Left ventricle LEFT VENTRICLE B. RIGHT VENTRICLE - Very thick wall (3 times thicker than Right ventricle) 1. Structures: - Structures: Trabecula carnae, Papillary muscles, Chordae a. Pulmonary sinus and cusps of pulmonary valve tendineae b. Lunule and nodules of pulmonary cusps c. Infundibulum - smooth, outerflow part d. Trabecula carnae e. Papillary muscles attaching to chordae tendineae that is attatched to the cusps of tricuspid valve f. Septomarginal trabecula (moderator band) - connects the anterior papillary muscle to the interventricular septum; it allows the passage of the part of the right Bundle of His extending between the interventricular septum up to the base of anterior papillary muscles. Figure II.C Left Atrium and Ventricle: Flap Opened in Posterolateral Wall of Left Ventricle 1. Left auricle 2. Mitral valve (Posterior and Anterior cusps) 3. Anterior papillary muscle Figure II.B Right Ventricle (opened) 4. Chordae tendineae 5. Left atrium 6. Left pulmonary veins  The septomarginal trabeculum (11), which conducts part of the 7. Ligamentum arteriosum right limb of the atrioventricular bundle from the interventricular 8. Arch of aorta Page 3 of 6 CMED 1A  (002) HEART AND CORONARY CIRCULATION (DISSECTION VIDEO) DR. LESLIE ASUNCION-VIADO| 12/14/20 NOTE: The left ventricle is significantly thicker than the right ventricle. It contains 2 papillary muscles whose chordae tendineae attach to the cusps of the mitral (left atrioventricular, or bicuspid) valve. The mitral valve looks like a bishop’s miter. Heart sounds (lub-dub) occur from the closing of the valves. The 1st heart sound results from the closing of the mitral and tricuspid valves, whereas the 2nd heart sound results from the closing of the aortic and pulmonic valves. Figure II.E Tricuspid Valve from the Right atrium The atrium has been opened by incising the anterior wall (2) and turning the flap outwards so that the atrial surface of the atrioventricular orifice is seen, guarded by the three cusps of the tricuspid valve – anterior (1), posterior (7) and septal (8). Figure II.D Left Ventricle 1. Anterior interventricular artery 2. Anterolateral papillary muscle 3. Aorta 4. Chordae tendineae 5. Circumflex coronary artery 6. Coarse trabeculations 7. Left atrium 8. Left bundle branch 9. Left ventricle open 10. Membranous septum 11. Mitral valve 12. Posteromedial papillary muscle 13. Pulmonary valve 14. Right coronary orifice Figure II.F Pulmonary, aortic and mitral valves The pulmonary trunk (12) and ascending aorta (3) have been cut off immediately above the three cusps of the pulmonary and aortic valves (7, 2 and 15, and 14, 10 and 6). The upper part of the left atrium (5) has been removed to show the upper surface of the mitral valve cusps (11 and 1). Page 4 of 6 CMED 1A  (002) HEART AND CORONARY CIRCULATION (DISSECTION VIDEO) DR. LESLIE ASUNCION-VIADO| 12/14/20 1. Anterior interventricular artery 2. Ascending aorta 3. Atrioventricular nodal artery 4. Circumflex artery 5. Coronal artery 6. Diagonal artery 7. Left main stem 8. Marginal branch of right coronary artery 9. Posterior interventricular branch of right coronary artery 10. Right coronary artery 11. Sinuatrial nodal branch Figure II.G Heart fibrous framework The heart is seen from the right and behind after removing both atria, looking down on to the fibrous rings (4) that surround the mitral and tricuspid orifices and form the attachments for the bases of the valve cusps. The cusps of the pulmonary valve (7, 2 and 13) are seen at the top of the infundibulum of the right ventricle (5), and the aortic valve cusps (12, 9 and 6) have been dissected out from the beginning of the ascending aorta. III. BLOOD VESSELS OF CORONARY CIRCULATION A. Right coronary artery → Inferior surface of the heart → Crux → Posterior interventricular artery → Right marginal branch on the inferior margin of the heart 2/3 of cases - Right dominance B. Left coronary artery - located between the pulmonary trunk and the auricle of the left atrium; it immediately divides into an anterior interventricular branch and a circumflex Figure III.B Cast of the heart and great vessels. From circumflex, it will continue to anastomose near the crux of the heart with the termination of the right coronary artery The base of the heart is its posterior surface, formed largely by C. Diagonal branch of the anterior interventricular branch - supplies the left atrium (7). Note that the base is not the part of the heart the left ventricle which joins the superior vena cava, aorta and pulmonary trunk; this part has no special name. The very small oblique vein of the left atrium (12) marks the point where the great cardiac vein (5) becomes the coronary sinus (4), but the junction is unusually far to the right so that the posterior vein of the left ventricle (14) joins the great cardiac vein (5) instead of the coronary sinus itself. The coronary sinus (4), which receives most of the venous blood from the heart, lies in the posterior part of the atrioventricular groove between the left atrium and left ventricle and opens into the right atrium. The coronary sinus normally receives as tributaries the great cardiac vein (5), middle cardiac vein (11), and the small cardiac vein, the posterior vein of the left ventricle (14) and the oblique vein of the left atrium (12). Figure III.A Cast of the coronary arteries, anterior. Page 5 of 6 CMED 1A  (002) HEART AND CORONARY CIRCULATION (DISSECTION VIDEO) DR. LESLIE ASUNCION-VIADO| 12/14/20 TEST YOUR KNOWLEDGE III. Draw the gross anatomy of the heart (anterior and posterior picture) I. MCQ 1. Base of the heart is located at the ___. a. Inferior surface b. Superior surface c. Posterior surface d. Anterior surface 2. It is where the heart rests. a. Inferior surface b. Superior surface c. Posterior surface d. Anterior surface 3. Moderator band. a. Trabecula carnae b. Septomarginal trabecula Anterior surface of the heart c. Chordae tendineae d. Interventricular septum 4. Artery located at the anterior interventricular groove. a. Anterior interventricular artery b. Left anterior descending artery c. Both d. None 5. Border that separates the rough and smooth surfaces of right atrium. a. Musculi pectani b. Crista terminalis c. Fossa ovalis d. Limbus II. True or False. Base (Posterior surface) of the heart 1. Right coronary artery is more elastic than the Great cardiac vein. 2. Middle cardiac vein is thicker than Posterior interventricular REFERENCES artery. 1. https://youtu.be/m23OoqJH93U 2. McMinns’s & Abraham’s Clinical Atlas of Human Anatomy. 7th 3. The heart lies on its posterior surface. edition 3. Netter Atlas of Human Anatomy. 7th edition 4. Left ventricle is thicker than the right ventricle. 4. Gray’s Anatomy for Students. 3rd edition 5. Diagonal branch of the anterior interventricular branch supplies the left ventricle. ANSWERS: I. C A B C B II. T F F T T Page 6 of 6 CMED 1A