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Heart.pptx
- 1. Heart Dr. Muhammad Adnan Lecturer(anatomy) DCIMC
- 4. Introduction • The heartis a hollow, somewhat conical muscular blood pumping organ situated in the middle mediastinum and covered by the pericardium • It consist of 4 chambers- Right and left atrium Right and left ventricles Atrium are separated from each other internally by inter-atrial septum Ventricles are separated from each other internally by inter ventricular septum Right atrium and right ventricles are called right heart Left atrium and left ventricles are called left heart
- 5. • AURICLE OFTHE HEART- Auricle refers to an ear-shaped pouch in the atrium of the heart. Each auricle is attached to the anterior surface of each atrium. Thereby, the two auricles are called the left auricle and the right auricle. Auricle is a wrinkled structure. The major purpose of the auricle is to increase the capacity of each atrium.
- 6. Anatomical points • Thisis the viscera of heart with pericardium and great vessels 1. Apex is directed downward ,forward and to the left 2. Base is directed upward, backward and to the right 3. Sternocostal surface is directed forward and upwards 4. Diaphragmatic surface is downward and somewhat backwards
- 7. • Diameters ofheart- Apex to base -12cm Transverse – 8 to 9cm Antero-posterior- 6cm • Weight of heart- Adult male- 280-340gm/ average 300gm Adult female- 230-280gm/ average 250gm
- 8. External features • Heartpresent – apex, base, three surfaces and three borders Surfaces- 1. Sternocostal surface 2. Diaphragmatic surface 3. Left surface Borders – 1. Inferior border 2. Right border 3. Left border
- 9. Apex- it isa conical area formed only by left ventricle. Location -It is situated in the left 5th intercostal space 9cm lateral to the midsternal line, just medial to the midclavicular line. But in the new born apex beat is usually felt in the left 4th intercostal space at or just lateral to midclavicular line . After about 2years it reaches the adult position. Base- the base of the heart is called its posterior surface. it is formed by two atrium ; 2/3rd by left atrium and 1/3rd by right atrium Vertebral relation of the base- T5 - T8 in lying position T6 - T9 in erect position
- 10. Relation of thebase 1. Oblique sinus 2. Posterior part of fibrous pericardium 3. Right pair of pulmonary veins 4. Right and left principal bronchus 5. Oesophagus 6. Descending thoracic aorta 7. Vagus nerve 8. Thoracic duct 9. Azygos and hemiazygos vein 10. Posterior mediastinal lymphnode
- 11. Clinical anatomy • Normally,the cardiac apex or apex beat is on the left side. In the condition called dextrocardia, the apex is on the right side. Dextrocardia may be part of a condition called situs inversus in which all thoracic and abdominal viscera are a mirror image of normal.
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- 15. • Sternocostal surface– formed by 1. Anterior surface right atrium and its auricle 2. A part of Anterior surface of left auricle 3. Anterior surface of right ventricle(2/3rd) 4. Anterior surface of left ventricle(1/3rd) Mainly by the right atrium and right ventricle and partly by the left ventricle and left auricle.
- 16. • Diaphragmatic surface Itis formed only by two ventricles- 2/3rd by left ventricle and 1/3rd by right ventricle This surface is related to diaphragm • Left surface- It is formed the left ventricle and partly by the left atrium and its auricle.
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- 18. • Right border– It is rounded and convex, formed by the right atrium Extends from the opening of superior venacava to inferior vena cava A shallow groove present on the right border known as sulcus terminalis which correspond with crista terminalis interiorly • Left border – It is an ill defined border, formed mainly by left ventricle and partly by left auricle Extend from left auricle to apex of the heart • Inferior border- It is sharp and formed mainly by the right ventricle. Small part near the apex is formed by left ventricle Extend from inferior venacava to apex of the heart Close to the apex, it presents a notch known as incisura apicis cordis
- 19. Great vessels ofthe heart Great vessels are the large vessels that bring blood to and from the heart. They are- • Superior venacava • Inferior venacava • Pulmonary trunk • Ascending aorta • Four pulmonary vein
- 20. Circulation • There are3 types of circulations – 1. Systemic circulation 2. Pulmonary circulation 3. Portal circulation
- 23. Structure /Wall ofheart • There are 3 layers in the wall of heart- 1. Epicardium- Formed by visceral layer of serous pericardium 2. Myocardium- formed by cardiac muscle 3. Endocardium- formed by endothelium/ simple squamous epithelium Blood vesels lies between epicardium and myocardium
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- 26. Grooves or sulcus •Externally both atrium and ventricles are separated by grooves 1. Two atrium are separated by interatrial groove 2. Two ventricles are separated by interventricular groove 3. Atrium separated from ventricles by atrioventricular groove /coronary sulcus • ‘C’ shape atrioventricular or coronary sulcus is divided into anterior and posterior parts. Anteriorly it is deficit due to pulmonary trunk and consists of right and left halves. Right half is oblique between right auricle and right ventricle, lodging right coronary artery. Left half is small between left auricle and left ventricle, lodges circumflex branch of left coronary artery. • The interatrial groove is faintly visible posteriorly, while anteriorly, it is hidden by the aorta and pulmonary trunk. • The anterior interventricular groove is nearer to the left margin of the heart. It runs downwards and to the left. • The posterior interventricular groove is situated on the diaphragmatic surface of the heart. It is nearer to the right margin of this surface. • These two interventricular grooves meet at the inferior border near the apex called incisura apicis cordis
- 27. Crux of theHeart • Crux of the heart is the meeting point of interatrial, atrioventricular and posterior interventricular grooves • Importance – it is a site for anastomosis of right and left coronary artery
- 28. Contents of groovesor sulci Contents of anterior interventricular groove- 1. Anterior interventricular branch of left coronary artery 2. Great cardiac vein 3. Nerve plexus 4. Lymphatics 5. Fat Contents of posterior interventricular groove- 1. Posterior interventricular branch of right coronary artery 2. Middle cardiac vein 3. Nerve plexus 4. Fat 5. Lymphatics
- 29. • Contents ofcoronary sulcus / atrioventricular groove- Right anterior part- trunk of right coronary artery Left anterior part- trunk and circumplex branch of left coronary artery, termination of great cardiac vein, commencement of coronary sinus Posterior part- coronary sinus Or you can say this way- 1. Right coronary artery 2. Circumflex branch of left coronary artery 3. Coronary sinus 4. Small cardiac vein 5. Nerve plexus 6. Lymphatics 7. fat
- 30. INTERIOR OF THEHEART • RIGHT ATRIUM -
- 32. • The interiorof the right atrium is divided into two parts: (a) main smooth posterior part – the sinus venarum, and (b) rough anterior part – the atrium proper. The two parts are separated from each other by crista terminalis Smooth Posterior Part or Sinus Venarum • Developmentally, it is derived from the right horn of the sinus venosus. • Most of the tributaries except the anterior cardiac veins open into it. a The superior vena cava opens at the upper end. b The inferior vena cava opens at the lower end. The opening of inferior vena cava is guarded by a rudimentary valve of the inferior vena cava or Eustachian valve. During embryonic life, the valve guides the inferior vena caval blood to the left atrium through the foramen ovale. c. The coronary sinus opens between the opening of the inferior vena cava and the right atrioventricular orifice. The opening is guarded by the valve of the coronary sinus or thebesian valve. d. The venae cordis minimae are numerous small veins present in the walls of all the four chambers. They open into the right atrium through small foramina. These are the small vein that drain from the myocardium into the right atrium
- 33. • Rough AnteriorPart • Developmentally, it is derived from the primitive atrial chamber. • It presents a series of transverse muscular ridges called musculi pectinati. • They arise from the crista terminalis(smooth muscle ridge) and run forwards and downwards towards the atrioventricular orifice, giving the appearance of the teeth of a comb.
- 34. Interatrial Septum It presents 1.The fossa ovalis, a shallow saucer-shaped depression, in the lower part. 2. The annulus ovalis or limbus (Latin a border) fossa ovalis is the prominent margin of the fossa ovalis. It is deficient inferiorly because of valve of the inferior vena cava. • The remains of the foramen ovalis are occasionally present(25%). This is a small slit-like valvular opening between the upper part of the fossa and the limbus. It is normally occluded after birth, but may sometimes persist. 3. Triangle of Koch, a triangular area bounded in front by the base of septal leaflet of tricuspid valve, behind by anterior margin of the opening of coronary sinus. The atrioventricular node lies in this triangle. 4. Torus aorticus, an elevation in the anterosuperior part of the septum produced due to bulging of the right posterior aortic sinus of ascending aorta.
- 35. Interior of theright ventricle
- 36. • The interiorof right ventricle consists of two parts: (a) a large, lower rough inflowing part, and (b) a small upper outflowing part, the infundibulum separated by the supraventricular crest Inflowing part shows trabeculae carneae or muscular ridges of three types: a. Ridges or fixed elevations- these are linear smooth muscle elevation b. Bridges- these connect the ventricular wall c. Pillars or papillary muscles • Papillary muscles are conical muscular projection,with one end attached to the ventricular wall, and the other end connected to the cusps of the tricuspid valve by chordae tendineae (Latin strings to stretch). There are three papillary muscles in the right ventricle— anterior, posterior and septal. Function- opening and closing of valve. • Cusps are formed by reduplication of endocardium • The septomarginal trabecula or moderator band is a muscular ridge extending from the ventricular septum to the base of the anterior papillary muscle. It contains the right branch of the AV bundle Outflow part- It is smooth and forms upper 1 inch conical part of the right ventricular chamber— the infundibulum, which gives rise to pulmonary trunk
- 39. Interventricular Septum • Theseptum is placed obliquely. • The upper 1/3rd of the septum is membranous and separates not only the two ventricles but also the right atrium and left ventricle. • The lower 2/3rd is thick muscular and separates the two ventricles. Blood supply- • Anterior 2/3rd by anterior interventricular branch of left coronary artery • Posterior1/3rd by posterior interventricular branch of right coronary artery
- 40. VALVES OF THEHEART • There are two pairs of valves in the heart, a pair of atrioventricular valves and a pair of semilunar valves. • The right atrioventricular valve is known as the tricuspid valve because it has three cusps. • The left atrioventricular valve is known as the bicuspid valve because it has two cusps. It is also called the mitral valve. • The semilunar valves include the aortic and pulmonary valves, each having three semilunar cusps.
- 41. Atrioventricular Valves 1 Bothvalves are made up of the following components. • a. A fibrous ring to which the cusps are attached • b. The cusps are flat and project into the ventricular cavity. Each cusp has an attached and a free margin, and an atrial and a ventricular surface. The ventricular surfaces are rough and irregular due to the attachment of chordae tendineae. The valves are closed during ventricular systole (contraction) by apposition of the atrial surfaces near the serrated margins. • c. The chordae tendineae connect the free margins and ventricular surfaces of the cusps to the papillary muscles. They prevent eversion of the free margins and limit the amount of ballooning of the cusps towards the cavity of the atrium. • d. The atrioventricular valves are kept competent by active contraction of the papillary muscles, 2 Blood vessels are present only in the fibrous ring and in the basal one-third of the cusps. Nutrition to the central two-thirds of the cusps is derived directly from the blood in the cavity of the heart. 3 The tricuspid valve has three cusps. The three cusps—the anterior, posterior or inferior, and septal. 4 The mitral or bicuspid valve has two cusps—a large anterior or aortic cusp, and a small posterior cusp. The mitral cusps are smaller and thicker than those of the tricuspid valve.
- 42. Semilunar Valves 1 Theaortic and pulmonary valves are called semilunar valves because their cusps are semilunar in shape. Both valves are similar to each other. 2 Each valve has three cusps which are attached directly to the vessel wall, there being no fibrous ring.
- 43. CLINICAL ANATOMY • Thefirst heart sound is produced by closure of the atrioventricular valves. The second heart sound is produced by closure of the semilunar valves • Narrowing of the valve orifice due to fusion of the cusps is known as ‘stenosis’, viz. mitral stenosis, aortic stenosis, etc
- 44. CONDUCTING SYSTEM • Theconducting system is made up of myocardium that is specialized for initiation and conduction of the cardiac impulse. The conducting system has the following parts. 1 Sinuatrial node or SA node: It is known as the ‘pacemaker’ of the heart. It generates impulses at the rate of about 70–100 beats/min and initiates the heartbeat. It is horseshoe-shaped and is situated at the atriocaval junction in the upper part of the sulcus terminals. The impulse travels through the atrial wall to reach the AV node. 2 Atrioventricular node or AV node: It is smaller than the SA node and is situated in the lower and dorsal part of the atrial septum just above the opening of the coronary sinus. It is capable of generating impulses at a rate of about 40 to 60 beats/minute.
- 46. • 3 Atrioventricularbundle or AV bundle or bundle of His: It is the only muscular connection between the atrial and ventricular musculatures. It begins as the atrioventricular (AV) node crosses AV ring and descends along the posteroinferior border of the membranous part of the ventricular septum. At the upper border of the muscular part of the septum, it divides into right and left branches. • 4 The right branch of the AV bundle passes down the right side of the interventricular septum. A large part enters the moderator band to reach the anterior wall of the right ventricle where it divides into Purkinje fibres. • 5 The left branch of the AV bundle descends on the left side of the interventricular septum and is distributed to the left ventricle after dividing into Purkinje fibres. • 6. The Purkinje fibres form a subendocardial plexus. They are large pale fibres striated only at their margins. These generate impulses at the rate of 20–35 beats/minute.
- 47. • Blood supply:Whole of conducting system except left branch of AV bundle is supplied by right coronary artery. In 40% cases, left coronary artery supplies SA node. • CLINICAL ANATOMY Defects of or damage to conducting system results in cardiac arrhythmias, i.e. defects in the normal rhythm of contraction. Except for a part of the left branch of the AV bundle supplied by the left coronary artery, the whole of the conducting system is usually supplied by the right coronary artery. Why SA NODE IS CALLED PACEMAKER OF HEART- Pacemaker- pacemaker means regulator of motion. It is specialized cell or group of cells that automatically initiates and regulates the impulses of the heart. The normal cardiac pacemaker is SA node. Because- 1. Normal cardiac impulse 1st initiate(at a rate of 70-100/min) and maintained by the SA node 2. It discharge the rhythm most rapidly
- 48. FIBROUS SKELETON • Thefibrous rings surrounding the atrioventricular and arterial orifices, along with some adjoining masses of fibrous tissue, constitute the fibrous skeleton of the heart. It provides attachment to the cardiac muscle and keeps the cardiac valves competent. • There is large mass of fibrous tissue between the atrioventricular rings behind and the aortic ring in front. It is known as the trigonum fibrosum dextrum. . • Another smaller mass of fibrous tissue is present between the aortic and mitral rings. It is known as the trigonum fibrosum sinistrum. • The tendon of the infundibulum (close to pulmonary valve) binds the posterior surface of the infundibulum to the aortic ring
- 49. Functions of fibrousskeleton- 1. It forms the basis of electrical discontinuity between the atria and ventricle 2. Provide the attachment to atrial and ventricular musculature 3. It supports the valve of the heart 4. Maintain the shape and position of the heart
- 50. ARTERY SUPPLY OFTHE HEART
- 51. • The heartis supplied by two coronary arteries, arising from the ascending aorta. Both arteries run in the coronary sulcus. • Features of Coronary Arteries These arteries are ‘functional end arteries’. Though their branches anastomose with each other but one cannot compensate for the other artery in case of thrombosis.
- 52. RIGHT CORONARY ARTERY Origin •Right coronary artery is smaller than the left coronary artery. It arises from the anterior aortic sinus of ascending aorta. Course 1 It first passes forwards and to the right to appear between the root of the pulmonary trunk and the right auricle. 2 It then runs downwards in the right anterior coronary sulcus to the junction of the right and inferior borders of the heart. 3 It winds round the inferior border to reach the diaphragmatic surface of the heart. Here it runs backwards and to the left in the right posterior coronary sulcus to reach the posterior interventricular groove. 4 It terminates by anastomosing with the circumflex branch of left coronary artery at the crux.
- 53. Branches • Marginal branch •SA nodal branch • Posterior interventricular branch • Right conus artery • Area of Distribution • 1 Right atrium • 2 Ventricles: a. Greater part of the right ventricle, except the area adjoining the anterior interventricular groove. b. A small part of the left ventricle adjoining the posterior interventricular groove. • 3 Posterior one-third part of the interventricular septum. • 4 Whole of the conducting system of the heart except a part of the left branch of the AV bundle. The SA node is supplied by the left coronary artery in about 40% of cases.
- 54. LEFT CORONARY ARTERY •Origin Left coronary artery is larger than the right coronary artery. It arises from the left posterior aortic sinus of ascending aorta. • Course • 1 The artery first runs forwards and to the left and appear between the pulmonary trunk and the left auricle. Here it gives the anterior interventricular branch which runs downwards in the groove of the same name. The further continuation of the left coronary artery is called the circumflex artery. • 2 After giving off the anterior interventricular branch, the artery runs to the left in the left anterior coronary sulcus. • 3 It winds round the left border of the heart and continues in the left posterior coronary sulcus. At the crux, it terminates by anastomosing with the right coronary artery.
- 55. • Branches- • Anteriorinterventricular branch • Circumflex branch • Left diagonal branch • Left atrial branch • Pulmonary branch • Terminal branch • Area of Distribution 1 Left atrium 2 Ventricles: a. Greater part of the left ventricle, except the area adjoining the posterior interventricular groove. b. A small part of the right ventricle adjoining the anterior interventricular groove. 3 Anterior part of the interventricular septum 4 A part of the left branch of the AV bundle
- 56. CARDIAC DOMINANCE • Inabout 10% of hearts, the right coronary is rather small and is not able to give the posterior interventricular branch. In these cases, the circumflex artery, the continuation of left coronary, provides the posterior interventricular branch as well as to the AV node. Such cases are called left dominant. • Mostly, the right coronary gives posterior interventricular artery. Such hearts are right dominant. Thus the artery giving the posterior interventricular branch is the dominant artery
- 57. Collateral Circulation • CardiacAnastomoses The two coronary arteries anastomose with each other in myocardium. • Extracardiac Anastomoses The coronary arteries anastomose with the following. 1 Vasa vasorum of the aorta 2 Vasa vasorum of the pulmonary arteries 3 The internal thoracic arteries 4 The bronchial arteries 5 The pericardiacophrenic arteries • These channels may open up in emergencies when both coronary arteries are obstructed.
- 58. VEINS OF THEHEART
- 59. • VENOUS BLOODOF HEART DRAIN INTO RIGHT ATRIUM THROUGH- • 1. coronary sinus • 2. anterior cardiac vein • 3. venaecordis minimae Coronary Sinus • The coronary sinus is the largest vein of the heart. It is situated in the left posterior coronary sulcus. It is about 3 cm long. It ends by opening into the posterior wall of the right atrium. It receives the following tributaries: • 1 The great cardiac vein. • 2 The middle cardiac vein. • 3 The small cardiac vein. • 4 The posterior vein of the left ventricle. • 5 The oblique vein of the left atrium • 6 The right marginal vein Anterior cardiac vein- these are 3-4 in number. Drains the infundibulum of the right ventricle and ends directly into right atrium Venaecordis minimae- numerous small veins opens into different chambers of heart
- 60. LYMPHATIC DRAINAGE OFTHE HEART • The lymphatics of the heart accompany the coronary arteries, emerge from the fibrous pericardium along with the ascending aorta and pulmonary trunk in the form of two trunks. The right trunk drains into brachiocephalic nodes and left trunk drains into tracheobronchial nodes (at the bifurcation of the aorta).
- 61. NERVE SUPPLY OFHEART • Parasympathetic nerves reach the heart via the vagus. These are cardioinhibitory; on stimulation, they slow down the heart rate. • Sympathetic nerves are derived from the upper four to five thoracic segments of the spinal cord. These are cardio acceleratory, and on stimulation, they increase the heart rate, and also dilate the coronary arteries
- 63. CARDIAC PLEXUS • Bothparasympathetic and sympathetic nerves form the superficial and deep cardiac plexuses, the branches of which run along the coronary arteries to reach the myocardium. The superficial cardiac plexus is situated below the arch of the aorta in front of the right pulmonary artery. It is formed by: a. The superior cervical cardiac branch of the left sympathetic chain. b. The inferior cervical cardiac branch of the left vagus nerve. The deep cardiac plexus is situated in front of the bifurcation of the trachea, and behind the arch of the aorta. It is formed by all the cardiac branches derived from all the cervical and upper thoracic ganglia of the sympathetic chain, and the cardiac branches of the vagus and recurrent laryngeal nerves, except those which form the superficial plexus.
- 64. CLINICAL ANATOMY Myocardial infarction(MI): A sudden block of one of the larger branches of either coronary artery usually leads to myocardial ischemia followed by the myocardial necrosis (myocardial infarction). The part of heart suffering from MI stops functioning and often causes death. This condition is termed heart attack or coronary attack. • The clinical features of MI are as follows: 1. A sensation of pressure/sinking and pain in the chest that lasts longer than 30 minutes. 2. Nausea or vomiting, sweating, shortness of breath, and tachycardia. 3. Pain radiates to the medial side of the arm, forearm, and hand. Sometimes, it may be referred to jaw or neck.
- 65. • Angina pectoris:If the coronary arteries are narrowed, the blood supply to the cardiac muscles is reduced. As a result, on exertion, the patient feels moderately severe pain in the region of left precordium that may last as long as 20 minutes. The pain is often referred to the left shoulder and medial side of the arm and forearm. In angina pectoris pain occurs on exertion and relieved by rest. This is because the coronary arteries are so narrowed that the ischemia of cardiac muscle occurs only on exertion. Congenital anomaly of heart – 1. Abnormal position of the heart- Dextrocardia Situs inversus 2. Atrial septal defect (ASD)- 3. Ventricular septal defect (VSD) 4. Fallots tetralogy- a) Pulmonary stenosis b) Ventricular septal defect c) Overriding of aorta d) Right ventricular hypertrophy