Angiology ( 2 )

1. Angiology( 2 ) Department of Anatomy Luzhou Medical College Made by professor Xiao

2. Section 2 The heart 12cm • General Description • It is a hollow, muscular organ of a somewhat conical or pyramidal form. And it is a dynamic pump, which can drive blood to flow. The heart beat rhythmically. Thus its position, size and shape are variable with functional state. The heart size varies with body size, so that it is the size of a person’s fist. 8-9cm broadest 6cm anteroposteriorly Weight 280-340g in males, 230-280g in females

3. The location • The heart locating in the middle mediastinum of the thorax and resting upon the diaphragm, is enclosed in the pericardium. The heart is bordered laterally by the lungs, posteriorly by the fifth to eighth thoracic vertebra, and anteriorly by the body of the sternum and second to sixth costal cartilage.

4. The location • Two-third of the heart lies on the left of the median sagittal plane, and one-third on the right. the base of the heart lies beneath the second rib, its distal end extends downward, forward and to the left, terminating as a bluntly pointed apex at the level of the intercostal space. For this reason, it is possible to sense the apical heartbeat by feeling or listening to the chest wall between the fifth and sixth ribs, near or a little medial to the left midclavicular line.

5. The external features • An apex • A base • Two surfaces Three borders Four grooves

6. The external features • The Cardiac apex is formed by the left ventricle, and is conical in shape. The left lung and pleura overlap it. It is directed down, forwards and to the left. It is located most commonly behind the fifth left intercostal space, near or a little medial to the midclavicular line. Apex

7. The external features • The cardiac base is formed mianly by the left atrium, and only partly by the posterior part of the right atrium. This is somewhat quadrilateral, which has curved lateral extensions. It faces backward, upward and to the right. Two pulmonary veins on each side open into the left atrial part of the base, while the superior and inferior vena cava open into the upper and lower parts of the right atrial basal region. Base

8. The external features • The anterior surface or sternocostal surface • It faces forwards and upwards, it has an acute and a more gradual left convexity. The atrial area is occupied almost entirely by the right atrium. The left atrium is largely hidden by the ascending aorta and pulmonary trunk. Only a small part of the left appendage projects forward to the left of the pulmonary trunk. Of the ventricular region, about one-third is made up by the left and two-third by the right ventricle. This surface is covered by the pleura and by the thin, anterior edges of the lungs, except for the triangular area at the cardiac incisure of the left lung. Surfaces

9. The external features • The posterior or diaphragmatic surface • This surface is largely horizontal, it slopes down and forwards a little towards the apex. It is formed by two ventricles and rest mainly up on the central tendon of the diaphragm, but also, apically, on a small area of the muscular part the diaphragm. It is separated from the anatomic base by the coronary groove and is traversed obliquely by the posterior interventricular groove. Surfaces

10. The external features • The right border • Corresponding to the right atrium, its profile is slightly convex to the right and it approaches the ventricle. Borders

11. The external features Borders • The left border • Known as the obtuse margin, it is round and mainly formed by the left ventricle but, to a slight extent superiorly, is formed by the auricle of the left atrium. It descends obliquely, convex to the left, from the auricle to the cardiac apex.

12. The external features Borders • Inferior border • Also known as the acute margin of the heart, it is shape , thin and nearly horizontal. It extends from the lower limit of the right border to the apex and is formed mainly by the right ventricle, with a small contribution from the left ventricle near the apex.

13. The external features • The grooves on the cardiac surfaces • The division of the heart into four chambers produces boundaries visible externally as grooves or sulci. Some are deep and obvious and contain prominent structures. Others are less distinct, even barely perceptible, and are sometimes obscured, in part, by the major structures crossing then. • Coronary groove • Interventricular groove • Interatrial groove Grooves

14. The external features • This is a ring-like groove. It separates the atria and the ventricles, and is oblique. On the sternocostal surface the anterior part of the coronary groove is obliterated where it is crossed by the pulmonary trunk and behind this, the aorta from which originate the coronary arteries. Its right part descends between the right border and the inferior border of the heart, and then turns to the diaphragmatic surface. It separates the right atrium from the right ventricle. Its left part curves around the obtuse margin and descends to the diaphragmatic surface. It separates the left atrium from the left ventricle. Grooves • 1. The Coronary groove

15. The external features • On the diaphragmatic surface of the heart the left and the right parts of the coronary groove from the sternocostal surface converges and forms transverse sulcus, separating the atrium and the ventricles. In fact, the coronary groove originating from the left part of the sternocostal surface, passes through the diaphragmatic surface, and turns, finally, to the right part of sternocostal one. The main trunks of the coronary arteries, its accompanying veins and fat lie in this groove, as well as the coronary sinus in this groove on the diaphragmatic surface of the heart. Grooves • 1. The Coronary groove

16. The external features Grooves • Internally, the ventricles are separated by the septum, the mural margins of which correspond to the anterior and posterior interventricular grooves. The anterior interventricular groove, seen on the sternocostal surface of the heart, is near and almost parallel to the left ventricle obtuse margin. On the diaphragmatic surface, in contrast, the posterior interventricular groove is closer to the midpoint of the ventricular mass. Two interventricular grooves extend all the way from the coronary groove to the apical notch on the acute margin. This covering site is a little to the right of the true cardiac apex, and termed the cardiac apical incisure. • The interventricular • groove

17. The external features Grooves • The anterior and posterior interventricular grooves contain branches of the left and right coronary arteries, accompanying veins and fat etc.

18. Grooves Interatrial groove It is limited to the right and left atria on the posterior surface of the cardiac base. This is a vertical, short and shallow groove, and descends to the crux. There is not any structure in this groove.

19. The atioventricular crux is regarded as an important superficial mark of the heart. It is the point of junction of the coronary, interatrial and posterior interventricular grooves, and indicates that two atria and two ventricles are close each other here. The significant structures exist within the cardiac wall corresponding to the crux. The atioventricular crux

20. The sulcus terminalis It lies on the anterior lateral wall of the right atrium. This is a longitudinal shallow groove, from the superior vena cava to the inferior vena cava. The sulcus terminalis separates the sinus venarum from the atrium proper of the right atrium.

21. The cardiac chambers • Internally, the heart is divided into right and left halves, each half is subdivided into two chambers, communicating by means of the atrioventricular orifice. The upper two atria are separated by the interatrial septum, the lower two ventricles by the interventricular septum. The atria serve as receiving chambers for blood from the various parts of the body, the ventricles as pumping chambers.

22. The right atrium • The interatrial septum is oblique, so the right atrium is anterior as well as the right of the left atrium, also extending inferior to it . Its wall form the right upper part of the sternocostal surface, the convex right border and a little of the right side of the anatomic base of the heart. It sits on the right superior portion of the heart. It is thin-walled chamber, and includes anterior and posterior parts. The anterior part is termed atrium proper, and the posterior part is termed sinus venarum cavarum. The sulcus terminalis is the line of the two parts. The anterior wall of the atrium proper projects anteriorly to overlap the right side of the ascending aorta, and so forms an extensive triangular muscular pouch, which is termed the right auricle.

23. Right atrium Sinus venarum caverum Atrium proper Pectinate muscles Tricuspid valve Sinus venarum caverum Terminal crest Fossa ovalis Valve of inferior vena cava Orifice of coronary sinus Valve of coronary sinus

24. The right ventricle • The right ventricle extends from the right atrioventricular orifice nearly to the cardiac apex. The cavity of the right ventricle is divided into sinous part ( inflow tract) and infundibular part (outflow tract). Two parts are separated by the supraventricular crest, which is situated between the atrioventricular and pulmonary orifices. The crest is a thick, muscular, highly arched structure.

25. Right ventricle Pulmonic valves Conus Arteriosus Supra- ventricular crest Parietal band Conal papillary muscle Anterior cusp Septal cusp Inter- ventricular septum Posterior cusp Anterior papillary muscle Septal band Trabeculae carneae Moderator band or septomarginal trabecula

26. Right ventricle Aortic valve Pulmonary valve An. Sep. Pos. Bicuspid valve Tricuspid valve Posterior view

27. The left atrium • It extends behind the right atrium and constitutes the most part of the base of the heart. A small somewhat conical pouch, termed the left auricle, projects forwards from its upper left corner and overlaps the root of the pulmonary trunk. It is characteristically longer, narrower and more hooked than the right auricle. The pectinate muscles, fewer and smaller than in the right auricle, are confined to the inner surface of the auricle. The rest of the atrial cavity is smooth. Interiorly, the four pulmonary veins open into the upper posterolateral surfaces of the left atrium, two on each side, their orifices are not provided with valves. The left two veins frequently open via a common channel. The left atrioventricular orifice is the aperture between the left atrium and ventricle.

28. Left auricle The pectinate muscles, fewer and smaller than in the right auricle, are confined to the inner surface of the auricle Right pulmonary veins The rest of the atrial cavity is smooth

29. The left ventricle • It constitutes the inferior portion and the apex of the heart. The left ventricle is longer and narrower than the right one. In a transverse section its cavity is oval or nearly circular, with walls about three times thicker than those of the right ventricle. Like the right, the cavity of the left ventricle is also divided into two parts, a sinous part (inflow tract) and an aortic vestibule ( outflow tract). Two parts are separated by the anterior cusp of the bicuspid valve.

30. The left ventricle The sinous part or inflow tract constitutes the main part of the left ventricle, its inlet in the left atrioventricular orifice, which is oval and smaller than that of the right. The orifice is supported and surrounded by looped fibrous tissue, called the annulus of the bicuspid valve, to which attaches the bicuspid valve itself.

31. Left ventricle Inflow tract or sinous part Outflow tract or aortic vestibule R. ventricle Tricuspid valve Mitral valve Muscular interventricular septum Membranous interventricular septum

32. Aortic valve Left auricle Left atrium Mitral valve Anterior valve Anterior papillary muscle

33. Left ventricle Bicuspid valve An. Pos. Bicuspid valve Posterior view

34. Aortic valve Pulmonary valve Bicuspid valve Tricuspid valve Posterior view

35. R. ventricle Tricuspid valve Mitral valve Muscular interventricular septum Membranous interventricular septum

36. The special conduction system of the heart

37. Mitral vav. /aortic vav. Left atrium Posterior cusp Anterior cusp Commissural cusps Anterior papillary muscle Posterior papillary muscle Aortic sinus Aortic valve Orifice of R. coronary artery Anterior cusp Inter-ventricular part Anterior Papillary muscle Atrio-ventricular part

38. Tricuspid vav. Anterior cusp Atrio-ventricular part Inter-ventricular part Medial cusp Posterior cusp Posterior papillary m. Anterior papillary m.

39. Mitral vav. tricuspid vav.

42. Aortic orif. Aortic vav. Aortic sinus

43. Opening of the coronary artery Sinus of the coronary artery (Mitral Valve Complex)

44. Pulmonary vav.

45. Aortic vav

47. Structure of heart • The heart mainly consists of myocardium and a fibrous skeleton. Its surface is covered with the visceral layer of the serous pericardium. And , internally it is lined with the endocardium. • The fibrous skeleton of the heart • From epicardium to endocardium, and from the orifices of the greater veins to the roots of the arterial trunks, the intercellular spaces between contractile and conducting elements are everywhere permeated by the connective tissue. The amount of connective tissue varies greatly in arrangement and texture in different locations and it around the orifices constitutes the annuli, such as annulus of the tricuspid valve, elcetrophysiological discontinuity between the atrial and ventricular myocardial masses except at the site of penetration of the conduction tissue. Second, it functions as a stable but deformable base for the attachments of the fibrous cores of the atrioventricular valves.

49. The right fibrous trigone sits among the annuli of the bicuspid valve, the tricuspid valve and the aortic valve. Inferiorly it adheres to the muscular part of the interventricular septum, and forward connects with the membranous part of the interventricular septum. Because of its position located to the center part of the heart, it is also called the central fibrous body, the fibrous skeleton is strongest here. Fibrous trigone The left fibrous trigone sits between the annulus of bicuspid valve and the annulus of the aortic valve. This trigone is smaller than the right one.

50. Fibrous ring of valve of pulmonary trunk Fibrous skeleton Fibrous ring of aortic valve Left fibrous trigone Membranous part of interventricular septum Fibrous ring of mitral valve Fibrous ring of tricuspid valve Right fibrous trigone (central fibrous body)