Anatomy of the Heart.pdf

ANATOMY OF THE HEART OSABUTEY EMMANUEL KWAKU  CONTENTS Location (Mediastinum) Pericardium Orientation and surfaces Chambers and valves Vasculature Nerve supply Great vessels  MEDIASTINUM The mediastinum is a broad central partition that separates the two later...

ANATOMY OF THE HEART OSABUTEY EMMANUEL KWAKU  CONTENTS Location (Mediastinum) Pericardium Orientation and surfaces Chambers and valves Vasculature Nerve supply Great vessels  MEDIASTINUM The mediastinum is a broad central partition that separates the two laterally placed pleural cavities. the mediastinum is subdivided into several smaller regions. 1. Superior mediastinum 2. Inferior mediastinum i. Anterior ii. Middle iii. Posterior  Subdivisions of the mediastinum.  PERICARDIUM The pericardium is a fibroserous sac surrounding the heart and the roots of the great vessels. It consists of two components, fibrous pericardium serous pericardium The fibrous pericardium is a tough connective tissue outer layer that defines the boundaries of the middle mediastinum. The serous pericardium is thin and consists of two parts: the parietal layer lines the inner surface of the fibrous the visceral layer (of serous pericardium adheres to the heart and forms its outer covering. Different layers of the Pericardium PHRENIC NERVES AND PERICARDIACOPHRENIC VESSELS. Posterior portion of pericardial sac showing reflections of serous pericardium.  CARDIAC ORIENTATION In the thoracic cavity, the apex of this pyramid projects forward, downward, and to the left, whereas the base is opposite the apex and faces in a posterior direction.The sides of the pyramid consist of: a diaphragmatic (inferior) surface on which the pyramid rests ; an anterior (sternocostal) surface oriented anteriorly ; a right pulmonary surface a left pulmonary surface Schematic illustration of the heart showing orientation, surfaces, and margins. Base of the heart.  SURFACES OF THE HEART The anterior surface faces anteriorly and consists mostly of the right ventricle with some of the right atrium on the right and some of the left ventricle on the left. Heart in the anatomic position rests on the diaphragmatic surface ,which consists of the left ventricle and a small portion of the right ventricle separated by the posterior interventricular groove. The left pulmonary surface faces the left lung, is broad and convex, and consists of the left ventricle and a portion of the left atrium. right pulmonary surface faces the right lung, is broad and convex, and consists of the right atrium Anterior surface of the heart. Diaphragmatic surface of the heart.  EXTERNAL SULCI Internal partitions divide the heart into four chambers (i.e. two atria and two ventricles) and produce surface or external grooves referred to as sulci. The coronary sulcus circles the heart, separating the atria from the ventricles. As it circles the heart, it contains the right coronary artery, the small cardiac vein, the coronary sinus, and the circumflex branch of the left coronary artery. The interventricular sulcus (anterior and posterior) Sulci of the heart. A. Anterior surface of the heart. B. Diaphragmatic surface and base of the heart. Sulci of the heart. A. Anterior surface of the heart. B. Diaphragmatic surface and base of the heart.  RIGHT ATRIUM The right atrium consists of a main cavity and a small outpouching, the auricle. On the outside of the heart at the junction between the right atrium and the right auricle is a vertical groove, the sulcus terminalis , which on the inside forms a ridge, the crista terminalis. The main part of the atrium that lies posterior to the ridge is smooth walled. The part of the atrium in front of the ridge is roughened or trabeculated by bundles of muscle fibers, the musculi pectinati OPENINGS INTO THE RIGHT ATRIUM The superior vena cava opens into the upper part of the right atrium; it has no valve. It returns the blood to the heart from the upper half of the body. The inferior vena cava (larger than the superior vena cava) opens into the lower part of the right atrium; it is guarded by a rudimentary, nonfunctioning valve. It returns the blood to the heart from the lower half of the body. The coronary sinus ,which drains most of the blood from the heart wall opens into the right atrium between the inferior vena cava and the atrioventricular orifice. It is guarded by a rudimentary, nonfunctioning valve. Internal view of right atrium.  RIGHT VENTRICLE The walls of the right ventricle are much thicker than those of the right atrium and show several internal projecting ridges formed of muscle bundles. The projecting ridges give the ventricular wall a spongelike appearance and are known as trabeculae carneae. Composed of three types: moderator band prominent ridges the papillary muscles ,which project inward, being attached by their bases to the ventricular wall; their apices are connected by fibrous cords (the chordae tendineae ) to the cusps of the tricuspid valve. As the cavity approaches the pulmonary orifice it becomes funnel shaped, at which point it is referred to as the  RIGHT VENTRICLE CONT’D The tricuspid valve guards the atrioventricular orifice and consists of three cusps: anterior septal inferior (posterior). The free edges and ventricular surfaces are attached to the chordae tendineae.. The chordae tendinae connects the cusps to the papillary muscles The pulmonary valve guards the pulmonary orifice and consists of three semilunar cusps Internal view of the right ventricle. Posterior view of the pulmonary valve.  LEFT ATRIUM& LEFT VENTRICLE Left Atrium Similar to the right atrium, the left atrium consists of a main cavity and a left auricle. The left atrium is situated behind the right atrium and forms the greater part of the base or the posterior surface of the heart.Behind it lies the oblique sinus of the serous pericardium, and the fibrous pericardium separates it from the esophagus. The interior of the left atrium is smooth, but the left auricle possesses muscular ridges as in the right auricle. Openings into the Left Atrium The four pulmonary veins, two from each lung, open through the posterior wall and have no valves. The left atrioventricular orifice is guarded by the mitral valve. Left Ventricle The left ventricle communicates with the left atrium through the atrioventricular orifice and with the aorta through the aortic orifice. The part of the ventricle below the aortic orifice is called aortic vestibule The mitral valve guards the atrioventricular orifice. It consists of two cusps, anterior posterior The aortic valve guards the aortic orifice and is precisely similar in structure to the pulmonary valve. One cusp is situated on the anterior wall (right cusp) and two are located Left atrium. A. Internal view.. Internal view of the left ventricle. Anterior view of the aortic valve. Blood supply of the heart Cardiac vasculature. A. Anterior view. B. Superior view (atria removed). Cardiac vasculature. A. Anterior view. B. Superior view (atria removed). A. Anterior view of coronary arterial system. B. Left anterior oblique view of right coronary artery. C. Right anterior oblique view of left coronary artery. Left dominant coronary artery. Major cardiac veins. A. Anterior view of major cardiac veins. B. Posteroinferior view of major cardiac veins.  NERVE SUPPLY OF THE HEART The heart is innervated by sympathetic and parasympathetic fibers of the autonomic nervous system via the cardiac plexuses situated below the arch of the aorta. The sympathetic supply arises from the cervical and upper thoracic portions of the sympathetic trunks, and the parasympathetic supply comes from the vagus nerves.  GREAT VESSELS The great vessels of the heart function to carry blood to and from the heart. The great vessels of the thorax are the: pulmonary trunk Aorta superior vena cava inferior vena cava pulmonary veins  SURFACE ANATOMY OF THE HEART For practical purposes, the heart may be considered to have both an apex and four borders. The apex ,formed by the left ventricle, corresponds to the apex beat and is found in the fifth left intercostal space 3.5 inch (9 cm) from the midline. The superior border ,formed by the roots of the great blood vessels, extends from a point on the second left costal cartilage (remember sternal angle) 0.5 inch. (1.3 cm) from the edge of the sternum to a point on the third right costal cartilage 0.5 inch. (1.3 cm) from the edge of the sternum The right border ,formed by the right atrium, extends from a point on the third right costal cartilage 0.5 in. (1.3 cm) from the edge of the sternum downward to a point on the sixth right costal cartilage 0.5 in. (1.3 cm) from the edge of the sternum The left border ,formed by the left ventricle, extends from a point on the second left costal cartilage 0.5 in. (1.3 cm) from the edge of the sternum to the apex beat of the heart The inferior border ,formed by the right ventricle and the apical part of the left ventricle, extends from the sixth right costal cartilage 0.5 in. (1.3 cm) from the sternum to the apex beat  Surface Anatomy of the Heart Valves. The surface markings of the heart valves are as follows: The tricuspid valve lies behind the right half of the sternum opposite the fourth intercostal space. The mitral valve lies behind the left half of the sternum opposite the fourth costal cartilage. The pulmonary valve lies behind the medial end of the third left costal cartilage and the adjoining part of the sternum. The aortic valve lies behind the left half of the sternum opposite the third intercostal space. Where to listen for heart sounds?? To listen for valve sounds, position the stethoscope downstream from the flow of blood through the valves The tricuspid valve is heard just to the left of the lower part of the sternum near the fifth intercostal space. The mitral valve is heard over the apex of the heart in the left fifth intercostal space at the midclavicular line. The pulmonary valve is heard over the medial end of the left second intercostal space. The aortic valve is heard over the medial end of the right second intercostal space. Thank you