Surface Anatomy of the Heart PDF

Cardiovascular system Dr.Wallaa Alfalluji Surface Anatomy of the Heart The Pericardial Sac Fibrous part - Ligament to the sternum (Sternopericardial Ligament) - Inferiorly blends with the diaphragm - Holds the heart in place Parietal Layer - Outer...

Cardiovascular system Dr.Wallaa Alfalluji Surface Anatomy of the Heart The Pericardial Sac Fibrous part - Ligament to the sternum (Sternopericardial Ligament) - Inferiorly blends with the diaphragm - Holds the heart in place Parietal Layer - Outer layer Serous Layer - Inner layer - Attaches to the heart and great vessels The parietal and serous layers are one continuous layer that is reflected back on itself. In between the layers in a thin layer of fluid, which gives a frictionless environment. Phrenic Nerves - C3, C4, C5 - “C3, 4, 5 – Keeps you alive” - Motor and sensory to the diaphragm - Sensory to the pericardium - Descend anterior to the lungs - Right Phrenic nerve descends over the right atrium, left nerve over left atrium The Heart The Heart is in the chest, surrounded by the dual layered pericardium. It lies deep to the sternum, inferior to the great vessels and superior to the diaphragm. The anterior pericardial surface is attached to the posterior surface of the sternum via the Sternopericardiac ligaments. The inferior pericardial surface is fused with the diaphragm. Anterior Surface: Right Atrium and Ventricle Posterior Surface: Left Atrium and Ventricle 1 Cardiovascular system Dr.Wallaa Alfalluji Blood Vessels of the Heart The blood vessels of the heart are the coronary arteries and cardiac veins, which carry blood to and from most of myocardium. They run across the surface of the heart, just deep to the epicardium, normally embedded in fat. The coronary arteries are the first branches of the aorta, and arise from the left and right aortic sinuses respectively. The aortic sinuses arise from the root of the aorta, just superior to the aortic valve and pass around opposite sides of the pulmonary trunk. Right Coronary Artery (RCA) Supplies: Right atrium, SA and AV nodes and posterior part of IVS. Anterior Surface: The RCA travels in the right atrioventricular groove, passing posteriorly between the right atrium and ventricle. In 60% of people the RCA gives off the sinuatrial nodal branch, supplying the SA node. The RCA then continues down the atrioventricular groove and gives off the right marginal branch, which supplies the right border of the heart as it runs towards (but does not reach) the apex of the heart. After giving off this branch, the RCA turns to the left and continues in the atrioventricular groove to the posterior aspect of the heart. Posterior Surface: On the posterior surface of the heart, at the junction between the four heart chambers (the crux), the RCA gives rise to the atrioventricular nodal branch, which supplies the AV node. In ~67% of people the RCA then gives rise to the posterior interventricular branch, which descends in-between the ventricles, supplying adjacent areas of both ventricles and sending perforating interventricular septal branches into the interventricular septum. The terminal RCA then continues for a short distance in the posterior atrioventricular groove. 2 Cardiovascular system Dr.Wallaa Alfalluji Left Coronary Artery (LCA) Supplies: Most of the left atrium and ventricle, IVS and AV bundles, may supply AV node Anterior Surface: The LCA runs in the left atrioventricular groove, where it splits into two branches. The Anterior Interventricular Artery, (or Left Anterior Descending (LAD) Artery) runs in the anterior interventricular groove to the Apex, where it turns around the inferior border of the heart and commonly anastomoses with the posterior interventricular artery. The Anterior Interventricular Artery supplies adjacent parts of both ventricles, and the interventricular septum via interventricular septal branches. In many people the Anterior Interventricular Branch gives off the Diagonal Artery, which runs down the anterior surface of the Heart. The second branch from the LCA is the Circumflex Branch, which follows the atrioventricular groove to the posterior surface of the heart. Posterior Surface: The Left Marginal Branch of the Circumflex Artery runs down the left margin of the heart and supplies the left ventricle. Most commonly the Circumflex Artery terminates in the AV groove, but in one third of hearts it continues to the posterior interventricular groove. In 40% of people it also gives rise to the SA Branch, which supplies the SA Node. 1 Cardiovascular system Dr.Wallaa Alfalluji Venous Drainage of the Heart The Heart is drained by veins that empty into the Coronary Sinus and partly by small veins that drain into the right atrium. Coronary Sinus The main vein of the heart - a wide venous channel that runs from left to right in the posterior part of the atrioventricular groove. Great Cardiac Vein The main tributary of the coronary sinus. Its first part, the anterior interventricular vein begins near the apex of the heart and ascends with the anterior IV branch of the LCA. It turns left at the AV groove and runs with the circumflex branch of the LCA to reach the coronary sinus. Middle Cardiac Vein Accompanies the posterior IV branch (usually from RCA). Small Cardiac Vein Accompanies the right marginal branch of the RCA. Anterior Cardiac Veins Several small veins begin over the anterior surface of the right ventricle, cross over the AV Groove and usually end directly in the right atrium (i.e. not via Coronary Sinus) 4