Anatomy of Heart for first year medical students, prepared from fifth edition of BD Chaurasia's Human Anatomy Vol 1 textbook with pictures from Google

1. HeartPrepared by
Dr Harikrishna Kamath S
Assistant Professor
Dept of Rachana Shareera
Amrita School of Ayurveda

2. Definition
• Heart is a conical hollow muscular organ which help to pump blood to
various parts of the body.
• [in Greek – cardia so adjective cardia
in Latin – Cor so adjective coronary]

5. Location
• In middle mediastinum, covered by pericardium
• Is placed obliquely behind the body of the sternum and adjoining
costal cartilages, so that 1/3 is on right side of median plane and 2/3
on the left side

9. Dimensions
• Length - 12 cm
• Breadth – 9 cm
• Weight – 300 g (males)
250 g (females)

10. External features
• 4 chambers – RA, RV, LA & LV
• Grooves or sulci –
(1) Atrioventricular groove (coronary sulcus) – btw atria and ventricles
(2) Interatrial groove – separating two atria
(3) Interventricular groove – separating two ventricles
- Anterior interventricular groove
- posterior interventricular groove

11. • 1 apex
• 1 base (posterior surface)
• 4 Borders – upper, lower, right and left
• 5 Surface – 1. anterior / sternocostal surface
2. posterior (base)
3. inferior / diaphragmatic surface
4. left pulmonarysurface
5. right pulmonary surface

14. Apex of the heart
• Formed entirely by the left ventricle
• Directed downwards, forwards and to the left
• Situated in the left fifth intercostal space 9cm lateral to the
midsternal line

16. Base of the heart
• Posterior surface
• Formed mostly by Left atrium , partly by right atrium
• 4 pulmonary veins open into LA
• SVC and IVC open into RA

18. Borders
• Upper – slightly oblique - formed by two atria , chiefly LA
• Lower – horizontal - mainly RV; small part near apex by LV
• Right – vertical – RA
• Left – curved - Left ventricle, small upper part by LA

20. Surfaces
• Anterior/ sternocostal surface – mainly RA, RV ; partly LV, Left auricle
Area of superficial cardiac dullness- most of the sternocostal surface is
covered by the lungs, but a small area behind the cardiac notch is not
covered. This uncovered area produce dull sound on percussion .
Coronary sulcus and anterior interventricular groove seen
• Inferior surface / Diaphragmatic surface- rest on central tendon of diaphragm
- 1/3 by RV
-2/3 by LV
- posterior interventricular groove seen

21. • Left surface – mainly by LV; in upper part by Left auricle
• [Posterior surface – base]
• Right surface - RA

26. Fibrous skeleton of heart
• Constitute - the fibrous ring surrounding A-V valve and arterial
orifices and the adjoining mass of fibrous tissue
• Significance – provides attachment to the cardiac muscles
- keeps the valves competent
• The mass of fibrous tissue btw A-V rings behind and the aortic ring in
front is called Trigonum fibrosum dextrum
• Btw aortic and mitral rings – Trigonum fibrosum sinistrum
• Btw aortic and pulmonary rings – tendon of the infundibulum

31. Right atrium
• Right upper chamber of heart
• Receives venous blood from whole body through SVC and IVC
• Pumps blood to RV through right atrio ventricular(tricuspid) opening
• It forms the right border
• Part of upper border
• Anterior surface
• base

34. External features
• Elongated vertically receiving SVC at the upper end and IVC at the lower end
• The upper end of the RA is prolonged to the left to for right auricle
• Sulcus terminalis – a shallow vertical groove btw SVC and IVC along the right
border of the atrium
• It is produced by the internal muscular ridge called crista
terminalis
• Upper part of the sulcus contains the Sinuatrial node (SA node)
which act as the pace maker of the heart
• Right A-V groove separates RA from RV. This groove lodges right coronary
artery and small cardiac vein

36. Tributaries of RA
1. Superior vena cava
2. Inferior vena cava
3. Coronary sinus
4. Anterior cardiav veins
5. Venae cordis minimi (Thebesian veins)
6. Sometimes Right marginal veins

37. Internal features
• 3 parts
 smooth posterior part / Sinus venarum
 Rough anterior part / pectinate part , including the auricle
 interatrial septum

39. Sinus venarum (smooth post. part)
• Most tributaries open here except anterior cardiac veins
• The SVC opens at the upper end
• Just below the opening of the SVC , on the posterior wall there is a small
projection called intervenous tubercle of Lower. During fetal life it directs
bllod from SVC to RV
• The opening of IVC is guarded by a rudimentary valve of the IVC or
Eustachian valve. During fetal life this valve guides the blood from IVC to
LA through foramen ovale.
• Coronary sinus open btw opening of IVC and tricuspid(R A-V) opening

40. Pectinate part (rough ant.)
• It presents a series of transverse muscular ridges called musculi
pectinate
• They arise from crista terminalis
• They run forwards and downwards to A-V orifice , giving the
appearance of teeth of a comb. (pectinate = comb like)
• In auricle muscles are interconnected to form a reticular network.

41. Interatrial septum
• Fossa ovalis – a shallow depression in the lower part of the
septum.
• it is the closed part of foramen ovale of fetal heart
• Annulus ovalis or limbus ovalis – is the prominent margin of
fossa ovalis

43. Right ventricle
• Triangular chamber which receives blood from right atrium and
pumps to lungs through pulmonary trunk and pulmonary arteries
• Its forms the inferior border, large part of anterior surface and 1/3 rd
part of inferior surface
• Semicircular in cross section

44. Features
• The interior has 2 parts :-
1. The inflowing part- rough due to the presence of muscular ridges
called trabeculae carneae
2. The out flowing part – or infundibulum – forms the upper conical
part of the right ventricle which give rises to pulmonary trunk
• The two parts are separated by a muscular ridge called
supraventricular crest or infundibulo-ventricular crest , situated btw
the tricuspid and pulmonary trunk orifice.

46. 2 orifices
1. Right atrioventricular orifice or tricuspid orifice, guarded by
tricuspid valve
2. Pulmonary orifice, guarded by pulmonary valve

47. 3 types of trabeculae carneae
• Muscular ridges are of 3 types
1. Ridged or fixed elevations
2. Bridges
3. Pillars or Papillary muscles
 one end of papillary muscle is attached to ventricular wall and
other end is connected to the cusps of the valve by chordae
tendinae
There are 3 papillary muscle in RV – 1. Anterior (largest)
2. posterior
3. septal
Each papillary muscle is attached to adjacent sides of 2 cusps

50. Moderator band/ septomarginal trabeculae
• Is a muscular ridge extending from the ventricular
septum to the base of anterior papillary muscle
• It contain right branch of A-V bundle

53. Left atrium
• Is a quandrangular chamber situated posteriorly
• The part of LA which is projecting anteriorly is called left auricle.
• LA forms the
Greater part of upper border
Upper part of left border
Left 2/3 of the base
Parts of anterior and left surfaces
• LA receives oxygenated blood from lungs through 4 pulmonary veins and
pump it to LV through left A-V orifice or mitral orifice

55. Features
• Anterior wall of LA- interatrial septum
• Posteror wall of LA forms the anterior wall of oblique sinus
• 2 pairs of pulmonary veins open of each side of the posterior wall
• Greater part of interior is smooth ; musculi pectinate are present only
in the auricle in the form of network.
• Septal wall has fossa lunata corresponding to fossa ovalis of RA
• Tributaries are 4 pulmonary veins and a few venae cordis minini

58. Left ventricle
• Receives oxygenated blood from LA and pumps to aorta
• It forms
Apex of the heart
Small part of lower border
Major part of left border
Part of Anterior surface
2/3 of inferior surface
Major part of left surface

60. Features
• Externally 3 surface- ant, inf and left
• Internally 2 parts –
1. lower rough part with trabeculae carneae
2. upper smooth part – Aortic vestibule- which give rises
to ascending aorta
• there are 2 orifices – 1. left Atrioventricular / bicuspid/mitral orifice-
guarded by Left A-V/bicuspid/mitral valve
2. aortic orifice- guarded by aortic valve

61. • 2 papillary muscles – Anterior and posterior
• Chordae tendinae from both muscles are attached to both cusps of
mitral valve
• Cavity of LV is circular in cross section
• Walls of LV are 3 times thicker than the walls of RV

64. Valves of heart
 maintain unidirectional flow of blood
Prevent the regurgitation of blood in opposite direction
• 2 pairs
 right and left atrioventricular valve/tricuspid and bicuspid
 Pulmonary and aortic valves- semilunar valve- due to semilunar cusps
 Cusps are fold of endocardium strengthened by intervening layer of
fibrous tissue

67. Conducting system of heart
• Special myocardium which can initiate and conduct cardiac impulses
• Parts of conducting system of heart are –
1. Sinuatrial node / SA node
2. Atrioventricular node / AV node
3. Atrioventricular bundle / AV bundle / bundle of His
4. Right and left branches of bundle of His
5. Purkinje fibres

69. SA node
• Pace maker of heart
• Generates impulse at the rate of about 70/min and initiates heart
beat
• Situated at the atriocaval junction in the upper part of sulcus
terminalis
• The signals travels through the atrial wall to reach the AV node

70. AV node
• Smaller than SA node
• Situated in the lower posterior aspect of the atrial septum just above
the opening of coronary sinus
• Generates impulse at the rate of about 60/min

71. AV bundle / bundle of His
• It is the only muscular connection btw atria and ventricles
• Begins from AV node
• Cross AV fibrous ring and descends down along posteroinferior
border of membranous part of ventricular septum
• At the upper border of the muscular part of the septum it divides into
right and left branches.

72. Right and left branches of AV bundle
• Right branch descends along the right side of interventricular septum
• Large part of it enters the moderator band to reach anterior wall of
RV where it divides into Purkinje fibres
 left branch descends along the left side of IV septum to reach LV and
divides into Purkinje fibres

73. Purkinje fibres
• Forms subendocardial plexus of cardiac muscles
• They are large pale fibres , striated only at their margins
• Usually have double nucleus

75. Clinical aspect of conducting system
• Cardiac arrhythmias – defects in normal rhythm of contraction (heart
beat)
• Except for the part of left branch of bundle of His (which is supplied
by Left coronary artery), the whole of the conducting system is
usually supplied by the right coronary artery.
• Vascular lesions of heart can cause arrythmias

76. Blood supply of the heart
• Right and left coronary artery
• First branch of aorta
• From the aortic sinus of ascending aorta
• Right coronary artery from anterior aortic sinus
• Left coronary artery from left posterior aortic sinus
• [opposite to the cusp of semilunar valves the walls of the vessels are
slightly dialated to form the aortic and pulmonary sinus]

80. Right coronary artery
• Is smaller than left coronary artery
• Arises from anterior aortic sinus
Course
• It first passes forwards and to right to reach ant. Surface of heart
between the root of pulmonary trunk and right auricle
• Then runs downwards in right ant. Coronary sulcus to the junction of
right and inferior borders of the heart

81. • It winds around the inferior border to reach the diaphragmatic
surface.
• Here it runs backwards and to the left in rgt post. coronary sulcus and
reaches the post. interventricular groove.
• Here it terminates by anastomosing with the circumflex branch of left
coronary artery

83. Branches
• Large branches
1. marginal branch
2. posterior interventricular branch
• Small branches
1. nodal branch
2. right atrial br
3. infundibular br
4. terminal br

85. Area of distribution
• RA
• Ventricles-
greater part of right ventricle, except the area adjoining the
anterior interventricular groove
A small part of left ventricle adjoining the post. Interventricular
groove
• Post. part of IV septum
• Whole of conducting system of heart except a part of left branch of
bundle of His.

86. Left coronary artery
• Larger than right coronary artery
• Arises from the left posterior aortic sinus
• Course
• it first passes forward and to the left, btw the pulmonary trunk and
the left auricle.
Here it gives the anterior interventricular br which runs
downwards in ant. IV groove
The further continuation of the main branch is called the
circumflex artery

87. • Circumflex artery runs to the left in left anterior coronary sulcus,
• Winds round the left border and continues in left posterior coronary
sulcus
• Near post interventricular groove it terminates by anastomosing with
right coronary artery.

88. Branches
• Large br –
1. anterior interventricular br
2.circumflex br
3. diagonal br
4. br to diaphragmatic surface ventricle
• Small br
1. left atrial
2. pulmonary br
3. terminal br

89. Area of distribution
• LA
• Ventricles –
1. greater part of LV, except the area adjoining the posterior
interventricular septum
2. a small part of right ventricle adjoining the ant. IV groove
• Anterior part if interventricular septum
• A part of Left branch of bundle of His

90. Veins of the heart
1. Great cardiac vein
2. Middle cardiac vein
3. Small cardiac vein
4. Oblique vein of Left atrium coronary sinus – Right atrium
5. Posterior vein of left ventricle
6. Right marginal vein
7. Anterior cardiac vein – directly open into RA
8. Venae cordis minini/ Thebesian veins – open into all chambers

91. Coronary sinus
• Largest vein of heart
• Situated in left posterior coronary sulcus
• About 3cm long
• Opens into post wall of RA
• Tributeries – great cardiac vein, middle cardiac vein, small cardiac vein
oblique vein of LA, posterior vein of LV
right marginal vein

95. Lymphatics of heart
• Lymphatic vessels form Two trunks (R & L) which accompany coronary
arteries
• Right trunk ends in brachiocephalic nodes
• Left trunk ends in tracheobronchial lymph nodes

96. Nerve supply of the heart
• Parasympathetic fibres – through vagus nerve – cardioinhibitory
• Sympathetic fibres – T1-T5 thoracic segments – cardioacceleratory
• Both sympathetic and parasympathetic fibres form superficial and
deep cardiac plexus before supplying heart

97. Clinical anatomy
• Stenosis – narrowing of the orifice of the valve due to the fusion of
the cusps. Eg. Aortic stenosis, mitral stenosis
• Incompetence / regurgitation – incomplete closure of the valve due to
stiffening of the cusps leading to back flow of blood
Eg. Aortic regurgitation
• bradycardia- slow pulse or decreased heart rate
• Tachycardia- rapid pulse or increased heart rate
• Arrhythmia – irregular pulse or heart rate
• Palpitation – consciousness of one’s own heart beat

98. • Inflammation of pericardium - pericarditis
• Inflammation of myocardium - myocarditis
• Inflammation of endocardium – endocarditis
• Dextrocardia – the cardiac apex is on the right side
• Angina pectoris

100. Thank You
Dr Harikrishna Kamath S.