The document provides an overview of the anatomy of the human heart, describing the internal and external structures such as the chambers, valves, vessels, conduction system, and blood supply. Key details include the layers of the heart wall, the differences between the right and left sides of the heart, the function of the atria and ventricles, and the roles of the major arteries and veins in the cardiac circulation. The presentation aims to educate medical students on the gross and microscopic anatomy of the heart.

1. ANATOMY OF THE HEART
Moderator: Dr. Ravi Narayan,
Consultant Paediatric Cardiologist,
Presented by,
Dr. Agilan M.,
I year, PGDCC, M.S. Ramaiah- Narayana Hrudayalaya.

2. THE HUMAN HEART

4. Heart in pericardial cavity
4
Figure 18.1

5. Pericardium
• Pericardial cavity is lined by the pericardium.
• Pericardium – a double-walled sac around the
heart composed of:
1. A superficial fibrous pericardium
2. A deep two-layer serous pericardium
a. The parietal layer lines the internal surface of the
fibrous pericardium
b. The visceral layer or epicardium lines the surface of the
heart
They are separated by the fluid-filled pericardial cavity.
Pericardial fluid acts as a lubricant reducing friction.

7. The Function of the
Pericardium:
Protects and anchors the
heart
Prevents overfilling of the
heart with blood
Allows for the heart to work
in a relatively friction-free
environment
The clear tissue being Lifted up by the
scalpel Is the pericardium

8. Applied anatomy- Pericarditis
• Various pathogens may infect the
pericardium.
• The inflamed pericardial surfaces rub
against one another.
• Makes a distinct scratching sound.
• Cardiac tamponade could occur due to the
increased pericardial fluid in the
pericardial cavity. This condition restricts
the movement of the heart.

9. Cardiac Tamponade
Black looking structure is the heart bulging from the
pericardial sac.Not only pathogens can cause a
cardiac tamponade, but blunt force trauma can
also cause it.

10. External Heart: Anterior View
Chapter 18, Cardiovascular System
10
Figure 18.4b

11. Gross Anatomy
• A conical hollow muscular organ approximately the
size of your fist
• Location :
Middle mediastinum behind sternum,
costal cartilages of 3,4,5 ribs
Superior surface of diaphragm
Left of the midline
Anterior to the vertebral column,
• Directed forward and to left .
• Anterior most is the apex.
• Average measurement: 12cm X9cm
• Weight: 325±75 g in men
275± 75 g in women

12. External features
• Sulci:
1.Coronary (atrioventicular) sulcia) anterior
b) posterior
1.Interterial groove visible posteriorly
2.Interventricular sulci/ groove
3.Crux is the posterior basal surface at juction
of coronary and posterior interventricular
sulci and internally atrial septum joins the
venticular septum

13. Surfaces
• Diaphragmatic or inferior
• Anterior of sternocostal
• Left surface
Borders
• Right- SVC and RA
• Left- LV and La
• Inferior- RV and laterally LV

14. External Heart: Vessels that Supply/Drain
the Heart (Posterior View)
• Arteries – right coronary artery (in
atrioventricular groove) and the posterior
interventricular artery (in interventricular
groove)
• Veins – great cardiac vein, posterior vein
to left ventricle, coronary sinus, and
middle cardiac vein

15. The anterior and posterior interventricular sulci are shallower
depressions that mark the boundary line between the left
and right ventricles.
These areas usually contain a large amount of fat. The sulci
contain the arteries and veins that feed the heart.
The heart has an attached base and a free apex.
The inferior tip is called the apex.
In a typical adult the heart measures approximately 12.5 cm
from the base to the tip.
The apex reaches to the fifth intercostal space, 7.5 cm to the
left of the midline.

16. Surface Anatomy :
Right atrium anterior and to the right of left atrium.
Left atrium a midline structure
Right ventricle anterior and to the right of left
Ventricle.
Pulmonary artery anterior and to the left of aorta
Coronary arteries on surface follow A-V groove
and interventricular septum.

17. External Heart: Major Vessels of
the Heart (Anterior View)
•
•
Vessels returning blood to the heart include:
1. Superior and inferior venae cavae
2. Right and left pulmonary veins
Vessels conveying blood away from the heart
include:
1. Pulmonary trunk, which splits into right and left
pulmonary arteries
2. Ascending aorta (three branches) –
a. Brachiocephalic
b. Left common carotid
c. Subclavian arteries
17

18. External Heart: Vessels that
Supply/Drain the Heart (Anterior View)
• Arteries – right and left coronary (in
atrioventricular groove), marginal,
circumflex, and anterior interventricular
arteries
• Veins – small cardiac, anterior cardiac,
and great cardiac veins

19. External Heart: Posterior View
Chapter 18, Cardiovascular System
19

20. External Heart: Major Vessels of
the Heart (Posterior View)
•
Vessels returning blood to the heart
include:
1. Right and left pulmonary veins
2. Superior and inferior venae cavae
•
Vessels conveying blood away from the
heart include:
1. Aorta
2. Right and left pulmonary arteries

21. Anatomical position of the
heart from Grays Anatomy

22. Anomalous-Anatomical position
of the heart

24. OVERVIEW OF THE CARDIOVASCULAR
SYSTEM
• Pulmonary circuit
• Systemic circuit
• Arteries (Including the coronary arteries)
• Veins (Including the coronary veins)
• Capillaries (Arterioles & Venules)
• Four chambers of the heart

25. Pathway of Blood Through the Heart
and Lungs
• Right atrium  tricuspid valve  right ventricle
• Right ventricle  pulmonary semilunar valve 
pulmonary arteries  lungs
• Lungs  pulmonary veins  left atrium
• Left atrium  bicuspid valve  left ventricle
• Left ventricle  aortic semilunar valve  aorta
• Aorta  systemic circulation
25

29. Heart Wall
• Epicardium – visceral layer of the serous
pericardium
• Myocardium – cardiac muscle layer
forming the bulk of the heart
• Fibrous skeleton of the heart –
crisscrossing, interlacing layer of
connective tissue
• Endocardium – endothelial layer of the
inner myocardial surface

30. Walls of the
Heart

31. Myocardial Thickness and Function
Thickness of myocardium varies according to the function of the
chamber
Atria are thin walled, deliver blood to adjacent ventricles
Ventricle walls are much thicker and stronger
– right ventricle supplies blood to the lungs (little flow
resistance)
– left ventricle wall is the thickest to supply systemic circulation

32. Thickness of Cardiac Walls
Myocardium of left ventricle is much thicker than the right.

33. Chambers
of the heart
• Right atrium RA
• Right ventricle RV
• Left Atrium LA
• Left Ventricle LV
• When not filled with blood, the outer portion of
each atrium deflates and becomes a lumpy,
wrinkled flap.
• This extension is called the auricle (looks like
an external ear).

34. Cardiac Chambers
• a) Right atrium Wide based blunt
appendage, crista terminalis separates
trabeculated from non-trabeculated
portion.
• b) Left atrium Long, narrow appendage,
smooth walls.
• c) Right ventricle Coarsely trabeculated
inlet/sinus, outlet portion.
• d) Left ventricle Fine trabeculations
inlet/sinus and outlet portions.

35. Gross Anatomy of chambers: Frontal Section
Chapter 18, Cardiovascular System
35
Figure 18.4e

38. Atria of the Heart
• Atria are the receiving chambers of the
heart
• Each atrium has a protruding auricle
• Pectinate muscles mark atrial walls
• Blood enters right atria from superior and
inferior venae cavae and coronary sinus
• Blood enters left atria from pulmonary
veins

39. Right Atrium
•
-
SVC
IVC
Crista terminalis
Coronary sinus
Tricuspid valve
Fossa ovalis
Triangle of Koch
Tendon of Todaro
Inferior isthmus

41. Ventricles of the Heart
• Ventricles are the discharging chambers of
the heart
• Papillary muscles and trabeculae carneae
muscles mark ventricular walls
• Right ventricle pumps blood into the
pulmonary trunk
• Left ventricle pumps blood into the aorta
41

42. View from the right side of the heart.

43. 1
2
3
Chordae tendineae
Papillary muscle

45. Ventricular Differences
• The anatomical differences between the
right and left ventricles are as follows:
• The right ventricle is relaetively thin. The
left ventricle has a massive muscular wall.

46. Interventricular
septum

47. Interatrial
Septum. Lateral view

48. The pectinate muscles
are prominent
muscular ridges found
in the atrial walls

49. Left
Ventricle
Heart
Wall
Right Ventricle Heart Wall

50. Fibrous Skeleton Of The Heart

52. Heart Valves
• Heart valves ensure unidirectional blood flow
through the heart
• Atrioventricular (AV) valves lie between
the atria and the ventricles
– AV valves prevent backflow into the atria when
ventricles contract
• Chordae tendineae anchor AV valves to
papillary muscles
52

53. Atrioventricular Valves
• Prevent backflow of blood from the
ventricles back into the atria.
• Chordae tendineae and papillary muscles
play an important role in this process.
• Ventricular diastole the ventricles relax
and the ventricles refill.
• The chordae tendineae are loose and
offer no resistance to the flow of blood.

54. Heart Valves
54

55. Heart Valves

56. During ventricular systole the ventricles begin to contract
blood moving back towards the atria swings the cusps
together closing the valves.
The chordae tendineae and papillary muscles stops the
cusps from swinging into the atria.
If those two structures are cut or damaged the valves act
as swinging doors, and there is backflow, or
regurgitation.
Mitral valve damage can especially occur in women
after pregnancy.

57. Mitral valve -Anatomy

59. Anatomic Classification Schema:
Mitral Valve Segments
Duran Classification
Ann Thorac Surg 1998: 65:1025-1031.
J Heart Valve Dis 1995; 4:70-75.
Cardiol Clin. 2000; 18: 731-50.

60. Am Heart J. 2000;139: 378-87.

61. Mitral Valve Prolapse

62. Tricuspid Valve

64. Semilunar Heart Valves
• Semilunar valves prevent backflow of
blood into the ventricles
• Aortic semilunar valve lies between the
left ventricle and the aorta
• Pulmonary semilunar valve lies between
the right ventricle and pulmonary trunk
64

65. Atrioventricular Valve Function
Chapter 18, Cardiovascular System
65
Figure 18.9

66. Semilunar Valve Function
Chapter 18, Cardiovascular System
66
Figure 18.10

68. Aortic valve – Anatomy

69. Aortic Root - Anatomy
The AORTIC ROOT has four anatomic components:
• The aortic annulus or aortoventricular junction
• The leaflets
SINGLE
• The aortic sinuses or sinuses of Valsalva FUNCTIONAL
UNIT
• The sinotubular junction

70. Aortic Annulus (aortoventricular junction
N
L
Fibrous tissue
Anterior leaflet of the mitral valve
Membranous septum
Normal:
Marfan/Bicuspid aortic valve:
R
Myocardium
55%
65%
Histology:
The aortic root is in fibrous continuity with
the anterior leaflet of the mitral valve and
the membranous septum; connective
tissue (fibrous strands) unites the aortic
root to the interventricular septum.
45%
35%
Sinotubular
Junctinon

71. Valve Leaflets
They are attached to the aortic root in a semilunar fashion
The triangular space underneath the leaflet
(trigone) is part of the left ventricle.
The highest point of the trigone where the
leaflets meet is called the commissure. The
commissures are localised immediately
below the Sinotubular Junction.
The 2 trigones underneath the commissures
of the noncoronary leaflet are fibrous
structures, whereas the other underneath
the commissure between the right and the
left leaflets is mostly a muscular structure.

72. Sinuses of Valsalva
The segment of the arterial wall
of the aortic root delineated by a
leaflet proximally and by the
sinotubular junction distally is
called the aortic sinus or sinus
of Valsalva.
They are 3 elliptical inlets that
have a very important role in the
dynamics of circulation :
• Guaranteeing coronary artery
perfusion during systole;
•Creating eddies to close the
aortic leaflets during diastole

73. Sinotubular
Junction
It represents the terminal edge of the aortic root and it
is constituted by the imaginary line that connects
together the 3 commissures.
Young
adults
AA>STJ
Adults
AA =
STJ
BASE = Aortic Annulus (AA)
Elderly
AA<STJ

74. aortic valve calcification
aortic stenosis
AORTIC VALVE PATHOLOGY
aortic valve fibrosis

75. AR due to Abnormalities of the
Leaflets
Infective endocarditis
Trauma
Iatrogenic cause
Cusp perforation

76. AR due to Abnormalities of the
Leaflets
•
•
•
Excess of tissue
Disrupted commissure
Commissural malposition
Cusp prolapse

77. AR due to Abnormalities of the
Leaflets
Fibrous thickening
Restrictive motion

78. AR - Abnormalities of the Aortic
SinotubularWall dilatation
junction
Dilatation of the sinotubular junction displaces the commissures outward and prevents
the aortic leaflets from coapting, with resulting central aortic insufficiency

79. AR - Abnormalities of the Aortic Wall
•
• Marfan syndrome
•
Connective tissue
diseases
•
Ventricular dilatation
•
Chronic hypertension
Annular dilatation

80. AI due to Abnormalities of the Aortic Wall
Aortic root
aneurysm:
ST junction
dilatation
+
Sinuses of
Valsalva aneurysm

81. CONDUCTION SYSTEM

82. Conduction System
• Sinoatrial node - anterolateral RA
• Interatrial conduction pathways - not well defined and
somewhat controversial
• Inferior isthmus (right atrium) anterior Bachman's bundle (left
atrium), middle Wenkebachs, posterior Thorel
• Atrioventricular node - triangle of Koch
• Bundle of His - AV node to membranous septum, usually
located on the inferior/posterior wall of the membranous
septum
• Left bundle branch - left ventricular septal surface into multiple
branches
• Right bundle branch - below medial papillary muscle via
septal and moderator bands to anterior papillary muscle

89. IMPULSE
SA NODE

91. Heart Blood Supply
• Coronary circulation demands high
oxygen and nutrients for the cardiac
muscle cells.
• Coronary arteries originate at the base of
the ascending aorta.
• Interconnections between arteries called
anastomoses ensure a constant blood
supply.

93. Coronary Circulation: Arterial
Supply

94. Coronary Circulation: Venous
Supply
Chapter 18, Cardiovascular System
94
Figure 18.7b

95. Great, Posterior, small,
Anterior, Middle Cardiac
Veins carry blood from
The coronary capillaries
To the coronary sinus.
Left coronary artery supplies
The left ventricle. Circulflex
Curves left meeting with
The right coronary artery.
Left anterior decending
Supplies the posterior
Decending artery
(interventricular).

96. Microscopic Anatomy of Heart
Muscle
• Cardiac muscle is striated, short, fat,
branched, and interconnected
• The connective tissue endomysium acts as
both tendon and insertion
• Intercalated discs anchor cardiac cells
together and allow free passage of ions
• Heart muscle behaves as a functional
syncytium
InterActive Physiology®:
Cardiovascular System: Anatomy Review: The Heart
96

97. Microscopic Anatomy of Heart
Muscle
Chapter 18, Cardiovascular System
97
Figure 18.11

98. Extrinsic Innervation of the Heart
• Heart is
stimulated by the
sympathetic
cardioaccelerator
y center
• Heart is inhibited
by the
parasympathetic
cardioinhibitory
center

99. Thank