The pericardium has two layers - the fibrous pericardium and serous pericardium. The fibrous pericardium is a dense connective tissue that protects the heart. The serous pericardium contains two layers that lubricate the heart and prevent friction. It also contains the pericardial cavity filled with fluid. Too much fluid in the cavity can cause compression of the heart.

1. Pericardium
(******Short Note)
Introduction: The pericardium is a fibroserous sac that contains the heart and the roots of the great
vessels.
Layers of Pericardium:
There are two layers to the pericardial sac:
1. Fibrous pericardium
2. Serous pericardium.
1. Fibrous pericardium

The fibrous pericardium is the most superficial layer of the pericardium.

It is a cone shaped bag with a truncated apex directed above.

It is a dense connective tissue, protecting the heart, anchoring it to the surrounding
walls, and preventing it from overfilling with blood.

Above, it fuses with the outer adventitial layer of the neighboring great blood vessels.

Below it is firmly attached to the central tendon of the diaphragm.

In front it is attached to the upper & lower ends of the body of the sternum by the
superior & inferior sterno-pericardial ligaments.
2. Serous pericardium

The serous pericardium is deeper than the fibrous pericardium.

It is a closed sac & lies within the fibrous pericardium.

It contains two layers, both of which function in lubricating the heart to prevent friction
from occurring during heart activity

The layer adherent to the fibrous pericardium is the parietal layer.

The layer deep to the fibrous pericardium is the visceral layer. It is also called as the
epicardium.
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2. 
In between the parietal and visceral pericardial layers there is a space called the
pericardial cavity.

It is normally lubricated by a film of pericardial fluid.

Applied aspect of Pericardial cavity: Too much fluid in the cavity (such as in a
pericardial effusion) can result in pericardial tamponade, compression of the heart
within the pericardial sac.

The continuity between parietal & the visceral layers is established in the form of two
tubes.
-
one tube surrounds the ascending aorta & the pulmonary trunk (arterial end of
the primitive heart)
-
the second tube surrounds the four pulmonary veins, the superior & the inferior
venae cava (venous end of the primitive heart)
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3. 3. Pericardial sinus (Short note)
The pericardial sinuses are pockets in the pericardial cavity.
There are two Pericardial sinuses:

Transverse and

Oblique.
Transverse Sinus: The passage between the venous and arterial mesocardia—i.e., between the
aorta and pulmonary artery in front and the atria behind—is termed the transverse sinus.
Clinical Importance of transverse sinus: The catheter is passed through this sinus to occlude
the main vessels of heart during open heart surgery.
Oblique Sinus: The cul-de-sac enclosed between the limbs of the inverted-J of the venous
mesocardium, lies behind the left atrium and is known as the oblique sinus.
Anatomical Importance of Oblique sinus: It acts as bursa for the frictionless movements of
heart in the pericardium. It is similar to lesser omentum of abdomen for the stomach.
Transverse Sinus
Oblique Sinus
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4. Arterial Supply of the Pericardium

Its main arteries are the pericardiacophrenic and musculophrenic arteries, which are
branches of the internal thoracic arteries.

It also receives pericardial branches from the bronchial, oesophageal, and superior
phrenic arteries.

The epicardium is supplied by the coronary arteries.
Venous Drainage of the Pericardium

Its veins are tributaries of the azygos systems of veins.

Pericardiacophrenic veins also enter the internal thoracic veins.
Nerve supply of the pericardium

The fibrous pericardium and the parietal layer of the serous pericardium are supplied by
the phrenic nerves

The visceral layer of the serous pericardium is supplied by the branches from the
sympathetic trunks and the vagus nerve
Applied Anatomy of the pericardium

Applied aspect of Pericardial cavity: Too much fluid in the cavity (such as in a
pericardial effusion) can result in pericardial tamponade, compression of the heart
within the pericardial sac.

Clinical Importance of transverse sinus: The catheter is passed through this sinus to
occlude the main vessels of heart during open heart surgery.
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5. HEART
(Long Question)
Introduction: Heart is vital organ and the central pump in the cardiovascular system.
It is a hollow, conical muscular organ.
Location: It is situated in the middle mediastinum.
Covering: Lies within the pericardium.
External Features of heart (Short note):
Heart presents:

Apex

Base (Posterior surface)

Three surfaces
o

Sternocostal, Diaphragmatic & Base(Posterior surface)
Three borders

Right, Inferior & Left borders.
Apex of the heart
The apex of the heart is the lowest superficial part of the heart.

It is directed downward, forward, and to the left

is overlapped by the left lung and pleura.

it is a conical area formed only by the LEFT VENTRICAL.

It lies behind the fifth left intercostal space, 8 to 9 cm. from the mid-sternal line, slightly medial
to the midclavicular line.

Alternately, it can be found about 4 cm. below and 2 mm. to the medial side of the left nipple
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6. Base of the heart

It is formed mainly by the left atrium, and, to a small extent, by the back part of the right atrium.

Somewhat quadrilateral in form.

It is in relation above with the bifurcation of the pulmonary artery, and is bounded below by the
posterior part of the coronary sulcus, containing the coronary sinus.

On the right it is limited by the sulcus terminalis of the right atrium, and on the left by the
ligament of the left vena cava and the oblique vein of the left atrium.
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7. 
The four pulmonary veins, two on either side, open into the left atrium, while the superior vena
cava opens into the upper, and the inferior vena cava into the lower, part of the right atrium
Sternocostal surface(anterior surface of the heart)

is directed forward, upward, and to the left.

Its lower part is convex, formed chiefly by the right ventricle.

traversed near its left margin by the anterior interventricular groove.

Anterior part of atrio-ventricular groove (Coronary sulcus) passes downwards & to the right
between right atrium & right ventricle
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8. 
The atrio-ventricular groove (Coronary sulcus)lodges the trunk of right coronary artery and
anterior cardiac vein.

Anterior interventricular groove is seen between right and left ventricles. It lodges anterior
interventricular branch of left coronary artery and great cardiac vein.
This surface is formed by the following parts of the heart:

Anterior surface of right atrium & its auricle.

A part of left auricle

Anterior surface of the right ventricle (2/3)

Anterior surface of the left atrium (1/3)
Diaphragmatic surface of heart (inferior surface)

Is directed downward and slightly backward

is formed by two ventricles -2/3 by left ventricle & 1/3 by the right ventricle.

rests upon the central tendon and a small part of the left muscular portion of the diaphragm.

It is separated from the base by the posterior part of the atrio-ventricular groove.

is traversed obliquely by the posterior interventricular groove.

In posterior interventricular groove run the posterior interventricular artery and middle cardiac
vein
Left surface

is directed upwards, backwards & to the left

is formed by mainly the left ventricle & partly by the left atrium & its auricle.

left part of the atrio-ventricular groove intervenes between left auricle & left ventricle. It
contains left coronary artery.
Right border of heart

is formed by the right atrium.

is rounded and almost vertical

Extends from the opening of superior venacava to that of inferior venacava.

A shallow groove known as the sulcus terminalis accompanies the right border.
Inferior border

Is sharp & nearly horizontal

It extends from the opening of inferior venacava to the apex of the heart.

Close to the apex it presents a notch, called the incisura apicis cordis.
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9. 
is named the acute margin
Left margin of heart (obtuse margin)

is shorter than the right border of heart

full and rounded.

it is formed mainly by the left ventricle, but to a slight extent, above, by the left atrium.
Heart consists of four chambers:

Right & Left atrium.

Right & Left ventricle.
External Features of heart:
Right Atrium: (******Short Note)
It forms the right border and part of sternocostal surface of the heart. It is separated from the right
ventricle by atrioventricular sulcus (coronary sulcus).
Interior of the right atrium is divided into three parts:
1. Rough part (Pectinate part)
2. Smooth part (Sinus venarum)
3. Septal part (Interatrial septum)
1. Rough part: (Pectinate part) (Anterior Part)
It is formed by anterior wall of the right atrium and also formed by right auricle.
Features seen:
Crista terminalis: It is sharp crest seen at the inner aspect of the right border of heart.
Musculi pectinati: This is comb like appearance of the rough part extending from the crista terminalis.
Right auricle: It is small ear like part of right atrium containing rough trabeculae within it.
Rough part embryologically is derived from the primitive atrium.
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10. 2. Smooth part (Sinus venarum) (Posterior part):
It is formed by the posterior wall of the right atrium.
Features seen:
Smooth wall received openings of the vein in to it.
Opening of Superior vena cava in the upper part.
Opening of Inferior vena cava in the lower part with valve of Inferior vena cava.
Opening of coronary sinus and its valve located just adjacent to opening of Inferior vena cava.
Smooth part emryologically is derived from the Sinus venosus. Hence it is known as Sinus venarum.
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11. 3. Septal part (Interatrial septum):
It is formed by interatrial septum.
Features seen:
Fossa ovalis: It is oval shaped depression. It is embryological remnant of Septum primum.
Limbus fossa ovalis: It is crescentic margin of the fossa ovalis. It is embryological remnant of Septum
secondum.
4. Atrioventricular valve: (Tricuspid valve): It is communicating right atrium
to right ventricle and formed by three cusps.
Right Ventricle (Short note):
It forms the part of sternocostal surface and diaphragmatic surface of the heart. It is separated from the
right atrium by atrioventricular sulcus (coronary sulcus) and from the left ventricle by anterior and
posterior parts of interventricular sulcus.
Wall the right ventricle is three times thinner than the wall of left ventricle. (Thin walled)
Interior of the right Ventricle is divided into two parts:
1. Rough part (Trabeculae carnae)
2. Smooth part (Infundibulum)
1. Rough part: (Trabeculae carnae)
It is formed by ridges, bridges and papillae.
Features seen:
Ridges: It is raised elevations from the wall of ventricle.
Bridges: It is raised elevations attached at two ends and free in between. Example of bridges is
Moderator band from interventricular septum to base of anterior papillary muscle.
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12. Papillae: It is conical nipple like projections from the wall of ventricle. There are three papillae in right
ventricle.
The papillae are also known as papillary muscles.
Anterior papillary muscle
Posterior papillary muscle
Septal papillary muscle (formed by small multiple papillae)
From the apex of the papillary muscles the thin strand extend to the margin of the leaflet (cusp) of the
atrioventricular (tricuspid) valve. These thin strands are known as Chordae Tendinae.
Rough part embryologically is derived from the primitive ventricle.
2. Smooth part (Infundibulum):
It is formed by the out-flowing smooth part which leads to pulmonary trunk. At its termination there is
pulmonary valve with three cusps.
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13. Smooth part embryologically is derived from the bulbus cordis.
3. Pulmonary valve at the junction of smooth part of right
ventricle and pulmonary trunk
4. Right Atrioventricular valve: (Tricuspid valve): It is communicating
right atrium to right ventricle and formed by three cusps.
Left Ventricle:
It forms the part of sternocostal surface and diaphragmatic surface of the heart. It is separated from the
left atrium by atrioventricular sulcus (coronary sulcus) and from the right ventricle by anterior and
posterior parts of interventricular sulcus.
Wall the left ventricle is three times thicker than the wall of right ventricle. (Thick walled)
Interior of the Left Ventricle is divided into two parts:
1. Rough part (Trabeculae carnae)
2. Smooth part (Vestibule)
1. Rough part: (Trabeculae carnae)
It is formed by ridges, bridges and papillae.
Features seen:
Ridges: It is raised elevations from the wall of ventricle.
Bridges: It is raised elevations attached at two ends and free in between.
Papillae: It is conical nipple like projections from the wall of ventricle. There are two papillae in left
ventricle.
The papillae are also known as papillary muscles.
Anterior papillary muscle
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14. Posterior papillary muscle
From the apex of the papillary muscles the thin strand extend to the margin of the leaflet (cusp) of the
atrioventricular (Mitral) valve. These thin strands are known as Chordae Tendinae.
Rough part embryologically is derived from the primitive ventricle.
2. Smooth part (Vestibule):
It is formed by the out-flowing smooth part which leads to Ascending aorta. At its termination there is
Aortic valve with three cusps.
Smooth part embryologically is derived from the bulbus cordis.
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15. 3. Aortic valve at the junction of smooth part of right ventricle
and Ascending aorta.
4. Left Atrioventricular valve: (Mitral valve): It is communicating left atrium
to left ventricle and formed by three cusps.
Left Atrium:
It forms the base of the heart or posterior surface of heart.
Interior of the left atrium is divided into three parts:
1. Rough part
2. Smooth part
3. Septal part
1. Rough part:
It is formed by left auricle.
Left auricle: It is small ear like part of right atrium containing rough trabeculae within it.
Rough part embryologically is derived from the primitive atrium.
2. Smooth part
It is formed by the posterior wall of the left atrium.
It receives two pulmonary veins on each side. Hence four pulmonary veins open into left atrium.
Smooth part embryologically is derived from absorption of pulmonary veins.
3. Septal part (Interatrial septum):
It is formed by interatrial septum.
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16. Features seen:
Fossa lunata: It is counterpart of fossa ovalis of right atrium.
4. Left Atrioventricular valve: (Mitral valve): It is communicating right
atrium to right ventricle and formed by three cusps.
Valves of the heart (viva)
1. Right atrioventricular (Tricuspid) valve: It is between right atrium and right ventricle.
It has three cusps: Anterior, Posterior and septal.
It is best auscultated at left fourth intercostal space just lateral to left sterna border.
2. Left atrioventricular (Mitral valve): It is between left atrium and left ventricle.
It has two cusps: Anterior and posterior.
It is best auscultated at left fifth intercostal space at midclavicular line.
3. Aortic valve: It is between left ventricle and ascending aorta.
It has three cusps: Anterior left, anterior right and posterior.
It is best auscultated at right second intercostal space just lateral to right sterna border.
4. Pulmonary valve: It is between right ventricle and pulmonary trunk.
It has three cusps: Anterior left, anterior right and posterior.
It is best auscultated at left second intercostal space just lateral to left sterna border.
General Structure of the Cardiac Wall

It consists of three layers:

The endocardium, the internal layer. This layer is continuous with the endothelium of the great
vessels.

The myocardium, the muscular layer.

The epicardium, the subepicardial fat and connective tissue beneath the visceral layer of the
serous pericardium.
Great vessels of the heart (Viva)
Ascending Aorta: Originating from the left ventricle.
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17. Pulmonary trunk: Originating from the right ventricle.
Superior Vena cava: Opening in the upper part of right atrium.
Inferior vena cava: Opening in the lower part of right atrium
Pulmonary veins: Four pulmonary veins. Two opens on each side of left atrium
Blood supply of heart (******Short Note)
Arterial supply:
Heart is supplied by right and left coronary arteries. Coronary arteries are functional end arteries. That
means even though it has anastomosis with each other in circumstances of blockage they are not able to
supply the area of blocked vessel and leads to infarction.
Right coronary artery:
Origin: Right anterior aortic sinus of ascending aorta.
Course:

It emerge between right auricle and pulmonary trunk.

It runs obliquely in the anterior part of the atriventricular (coronary sulcus).

At the lower border of heart, it turns posteriorly on the diaphragmatic surface in the posterior
part of coronary sulcus.

It gives posterior interventricular branch.

It terminates by anastomosing with circumflex branch of the left coronary artery.
Branches:

Nodal branch: supply in 80% people SA node.

Conal branch: supply aorta and pulmonary trunk.

Right marginal branch

Posterior interventricular branch which runs in posterior interventricular sulcus and terminates
by anastomosing with anterior interventricular branch of left coronary artery.
Area of distribution:

Right atrium
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18. 
Whole of right ventricle except small part adjacent to anterior interventricular sulcus.

Small part of left ventricle near the posterior interventricular sulcus.

Posterior half of interventricular septum.
Left coronary artery:
Origin: Left anterior aortic sinus of ascending aorta.
Course:

It emerge between left auricle and pulmonary trunk.

It gives anterior interventricular branch which runs in anterior interventricular sulcus.

Further continuation of left coronary artery is known as circumflex coronary artery which runs in
the posterior part of coronary sulcus.

It terminates by anastomosing with right coronary artery.
Branches:

Nodal branch: supply in 20% people SA node.

Conal branch: supply aorta and pulmonary trunk.
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19. 
Anterior interventricular branch which runs in anterior interventricular sulcus and terminates by
anastomosing with poterior interventricular branch of right coronary artery. This artery further
gives diagonal branches for the left ventricle.
Area of distribution:

Left atrium

Whole of left ventricle except small part adjacent to posterior interventricular sulcus.

Small part of right ventricle near the antterior interventricular sulcus.

Anterior half of interventricular septum.
Types of coronary circulation to the heart:
Right dominance: When the posterior interventricular artery is branch from the right coronary artery.
This type of circulation is present in most of the individuals.
Left dominance: When the posterior interventricular artery is branch from the left coronary artery. This
type of circulation is present in few individuals. This pattern is more prone to lead to Myocardial
infarction (Heart Attack)
Balanced type: When the posterior interventricular artery is branch from both right and left coronary
artery.
Applied Anatomy of Arterial supply:
As the coronary arteries are functional end arteries, blockage of any of the artery or its branch leads to
loss of blood supply to area of heart supplied by it. It leads to Myocardial infaction. (Heart Attack).
Venous drainage
Veins of the heart:
Coronary sinus (Short note):
largest vein of the heart.
Located in the posterior part of the coronary sulcus.
Tributaries:
Great cardiac vein
Middle cardiac vein
Anterior cardiac veins
Small cardiac veins
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20. Vein of left atrium
Termination: It opens in the right atrium of heart.
Great cardiac vein: Located in anterior interventricular sulcus drains in to coronary sinus.
Middle cardiac vein: Located in posterior interventricular sulcus drains in to coronary sinus.
Anterior cardiac veins: Located in coronary sulcus drains in to coronary sinus.
Small cardiac veins: drain into coronary sinus.
Vein of left atrium: drains in to coronary sinus.
Venae cordis minimi: Small veins directly open in to the chamber of heart.
Conducting system of Heart (Short note)
Sinuatrial node (SA node):
Located in the upper part of crista terminalis. Beating rate is 60-80 beats per minute. It is known as
pacemaker of heart.
Atrioventricular node (AV node):
Located just besides the atrioventricular valve in right atrium .
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21. Bundle of His:
Located in the membranous part of interventricular septum. Transmit impulses from AV node to
ventricles.
Right and left bundle branches:
Right and left branches of bundle of his respectively enter the right and left ventricles through
interventricular septum
Purkinje fibers:
Final terminal branches in the wall of the ventricles.
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22. Nerve supply of heart (viva)
Parasympathetic nerve supply: Vagus nerve (10th cranial nerve)
Stimulation of vagus is responsible for the decrease in the heart rate.
Sympathetic nerve supply: Cervical sympathetic chain containing
fibers from T1-T4 thoracic segments of spinal cord.
Stimulation of sympathetic nerves is responsible for the increase in the heart rate.
Applied Anatomy of heart (Viva)
Angina pectoris: temporary narrowing of the coronary arteries leads to severe excruciating pain in the
precordial region radiating to chin and left arm.
Myocardial infarction: It is serious condition due to sudden blockage of coronary artery or its branches
leading to loss of blood supply to myocardium causing ischemia of the sam.
Congenital heart diseases:
Atrial septal defect: Defect in the atrial septum which leads to mixing of oxygenated and deoxygenated
blood.
Vantricular septal defect: Defect in the interventricular septum which leads to mixing of oxygenated and
deoxygenated blood.
Valvular diseases of heart:
Narrowing of valves is known as stenosis e.g. Mitral stenosis
Incompetence of valve is known as regurgitation e.g. Mitral regurgitation.
Coronary angiongraphy: radiological study of vascular pattern of coronary arteries to identify any
blockage in the artery.
Coronary angioplasty: Repair of the block of the artery by putting stent in the coronary artery.
Bypass surgery for heart: Blocked coronary artery is bypassed by putting venous, arterial graft or by
transposition of vessel.
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