Transcript 16-Heart
By Prof. Saeed Abuel Makarem • • • • • • • Pericardium A fibro-serous sac Surrounds the heart & proximal part of its great vessels (Aorta, Pulmonary trunk, SVC, IVC, & 4 pulmonary veins) Formed of: Outer fibrous layer Inner serous sac Serous sac has 2 layers: Parietal & Visceral (epicardium) Fibrous Pericardium • Conical or flask shape • Apex: directed upwards fused with adventitia of 3 big vessels • Base: rests on diaphragm • Fuses with central tendon of diaphragm. • Posteriorly: Separated by post. Mediasinum from middle four thoracic vertebrae (5 to 8) • Anteriorly: body of sternum, costal cartilages ant. Border of lung & pleura, remains of thymus & 2 Sterno-pericardial ligaments • Extends from 2nd to 6th rib Function of serous pericardium: • 1- Lubrication to prevent friction • 2- Prevent adhesion of the heart to its surrounding Function of fibrous pericardium 1-Maintain the central position of the heart 2-Keeps large vessels open 3-Helps venous return 4-Acts as a wall for serous pericardium. 5- Prevents overdistention of the heart Serous pericardium Serous sac that has been invaginated by developing heart in fetal life Visceral layer: Epicardium. Parietal layer: Lines fibrous pericardium Pericardial cavity: potential space. • • • • • • • • Sinuses of pericardium 2 sinuses in serous pericardium (Transverse & Oblique) • Transverse sinus A recess behind pulmonary trunk & ascending aorta Boundaries: Ant: Pulmonary trunk & ascending aorta. Post: SVC &Upper part of the 2 atria Above: Rt. Pulmonary artery Below: the 2 atria mainly Lt. • Oblique sinus • It separates the base of heart (left atrium) from posterior mediastinum (descending aorta & esophagus) • Boundaries: • Ant: back of Lt. atrium • Post: fibrous pericardium & posterior mediastinum • Left: 2 Left pulmonary veins • Right: 2 right pulmonary veins & IVC Heart • Muscular pump that keeps circulation going on. • It is the size of hand’s fist of the same person • 2/3 of its breadth lies to left of median plane and 1/3 right to median plane • It is conical in shape having an apex, base, • Sterno-costal, diaphragmatic, surfaces • and right, and left borders. Apex • Directed downwards, forwards & to left • Lies in LT. 5th Intercostal space 3 & ½ inches ( 9 cm) from median plane. • Formed only by LT. ventricle. • Pericardium & diaphragm separate the apex from fundus of stomach • • • • • Base Directed backwards and slightly to right. Formed by 2 atria mainly the left atrium. Separated from post Mediastinum by oblique sinus of pericardium Lies opposite middle 4 thoracic vertebrae (5 to 8) Bounded inferiorly by coronary groove that lodge the coronary sinus. *Sterno-costal surface • Lies behind body of sternum & 3 to 6 costal cartilages. • Divided by coronary groove into: • Atrial part: Rt. Atrium • Ventricular part: the two ventricles, mainly Rt. • Borders: • Upper: Straight, formed by the 2 atrium but concealed by the ascending aorta & pulmonary trunk. • Lower: Concave formed by Rt. Ventricle & apical part of Lt ventricle • Rt.: Convex formed by Rt. Atrium • Lt.: Convex ,formed by Lt. auricle and Lt. ventricle. Surface anatomy of Heart • Point1: Lower border of 2nd Lt costal cartilage one & half inches from the median plane. • Point 2: Upper border of Rt. 3rd costal cartilage one inch from medial plane. • Point 3: Upper border of Rt. 6th costal cartilage one inch from its junction with the sternum. • Point 4: Apex Lt. 5th Intercostal space 3 ½ inches from median plane. Surface anatomy of the valves Pulmonary: Left 3rd sternocostal junction Aortic: Left 3rd Intercostal space just left to sternum Mitral: Left 4th sternocostal junction Tricuspid: 4th Intercostal space near the middle line. Auscultation of the cardiac valves Diaphragmatic surface • Left 2/3 of this surface are formed by Lt ventricle • Rt. 1/3 is formed by Rt. Ventricle • The 2 ventricles are separated by post. Interventricular groove. The groove lodges the post. Interventricular artery & middle cardiac vein Both coronary arteries lie in the atrioventricular groove (coronary Sulcus). While their branches lie in the interventricular grooves. • Right Coronary Artery: • It arises from ant. aortic sinus, at the root of ascending aorta • It passes forwards between Rt. auricle & pulmonary trunk. • Then it passes downwards and to the right in coronary groove to reach the lower margin of the heart Then it curves backward to runs in the posterior part of the coronary sulcus. Termination: By anastomosis with the circumflex branch of left coronary. Branches of right coronary artery: • 1- Marginal: Small branch passes along the lower • • • • • • border, from right to left. 2- Posterior interventricular artery (descending) : Medium sized, passes near its termination into the posterior interventricular groove to end in a poor anastomosis with the termination of the anterior interventricular artery, from the left coronary artery. 3- Small twigs to the ascending aorta and pulmonary trunk. 4- A branch to the S.A. node, which also supplies right atrium. 5- A branch to AV node. 6- Small branches to right atrium & right ventricle. So the right coronary supplies the right side of the heart and posterior part of the interventricular septum. Left coronary artery Origin: From Left posterior Aortic sinus, (larger than the Rt. Coronary). • Lies between left auricle and root of pulmonary trunk, till the anterior interventricular groove, where it divided into: • 1- Circumflex artery. • • • • • • 2- Anterior interventricular a. Branches: 1- Anterior interventricular. 2- Circumflex artery. 3- Diagonal artery. 4- Left marginal branch. Venous Drainage Of The Heart • Most of venous blood drains to Rt. Atrium, through coronary sinus which is the continuation of great cardiac vein. • It opens into Rt. Atrium to the left of IVC. • Small & Middle Cardiac veins are tributaries of coronary sinus. • Some blood drained into anterior cardiac vein to the Rt. Atrium. • Venae cordis minimi drain to all chambers of heart.