2. • Conical Fibro-serous sac
• Consists of
– fibrous pericardium
– serous pericardium
• Situated in the middle mediastinum
3.
4. Fibrous pericardium
• Conical sac and made up of fibrous tissue
• Keeps the heart in position and prevents over-distension of heart
• Important features to be noted
– Above: its apex is blends with the external coat of ascending
aorta and pulmonary trunk and is continuous with the pre-
tracheal fascia of deep cervical fascia
– Below: fuses with the central tendon of diaphragm
– Anteriorly: attached to the upper and lower end of the body
of the sternum by superior and inferior sternopericardial
ligaments
– Posteriorly: related to the principal bronchi, oesophagus and
descending thoracic aorta
– On each side related to the mediastinal pleura and
mediastinal surface of the lung
5.
6. Serous pericardium
• Thin, double layered serous membrane
• Lies within the fibrous pericardium
• Hence consists of
– Outer layer: parietal pericardium
– Inner layer: visceral pericardium or epicardium
7.
8. • Parietal pericardium
– fused with the fibrous pericardium
• Visceral pericardium or epicardium
– fused with the heart except along the cardiac grooves,
where it is separated from the heart by blood vessels
• Two layers continuous with each other at the root of great
vessels
• Between visceral and parietal pericardium there is a potential
space called pericardial cavity, which contains lubricating fluid
to allow free movement of heart.
9. • The parietal layer of serous pericardium is continuous
with the visceral layers of serous pericardium around
the roots of the great vessels. These reflections of
serous pericardium occur in two locations:
– one superiorly, surrounding the arteries, the aorta and
pulmonary trunk i.e. Transverse sinus
– the second more posteriorly, surrounding the veins, the
superior and inferior vena cava and the pulmonary veins i.e.
Oblique sinus
10.
11.
12. Contd…
• Arterial supply
– Fibrous and parietal pericardium: by branches of internal thoracic and
descending thoracic aorta
– Visceral layer: by coronary arteries
• Venous drainage
– Fibrous and parietal pericardium: drain into the azygos vein and internal
thoracic vein
– Visceral layer: drains into coronary sinus
• Nerve supply
– Fibrous and parietal pericardium: by phrenic nerve (C3-C5): thus they
are sensative to pain
– Visceral pericardium: by autonomic nerves (sympathetic and
parasympathetic (vagus nerve)
• Thus they are not sensative to pain
• Pain of pericarditis originates in the parietal pericardium alone
– commonly referred to the skin (C3-C5 dermatomes) of the ipsilateral
supraclavicular region (top of the shoulder of the same side).
13. Heart
• Hollow, conical muscular organ
• Measurements
– Length:
• 12 cm from apex to base
• 6 cm anteroposteriorly
– Widest transverse diameter: 9 cm
– Weight::
• about 280-340 gm (average 300 gm) in male and
• 230-280gm (average 250gm) in female
• Situated in the middle mediastinum (one-third part
lies to the right and two-third part lies to the left
14. Has
Apex and base
3 surfaces
Sternocostal (anterior)
Diaphragmatic (inferior) and
Left
4 borders
Upper
Right
Inferior and
Left
Grooves or sulci
atrioventricular or coronary sulcus,
interatrial groove,
anterior and posteroir interventricular grooves.
Two interventricular grooves meets at the inferior border
near the apex.
15. Apex of the heart
Formed only by the left
ventricle
Directed downwards, forwards
and to the left
Situated in the left 5th
intercostal space, about 9 cm
lateral to the midsternal line
and slightly below and medial
to the left nipple (just medial
to the midclavicular line
In the newborn apex beat
is usually felt in the left 4th
intecostal space at or just
lateral to the midclavicular
line; after about 2 yrs it
reaches the adult position
16. Base of the heart
Most fixed part of the heart and
also called its posterior surface
Formed mainly by the left atrium
(2/3rd) and partly by the right
atrium (1/3rd)
Features:
SVC and IVC open into right
atrium
Four pulmonary veins open
into left atrium
17. Borders of the heart
• Upper border:
• Formed mainly by the left
atrium and partly by the right
atrium
• Anterior to it are the
ascending aorta ad the
pulmonary trunk
18. Right border
formed by the right atrium
Extends from the right side
of the opening of SVC to
that of IVC
vertical and slightly convex
A shallow vertical groove
called sulcus terminalis
accompanies the right
border and corresponds
with crista terminalis in the
interior of right atrium
Contd…
19. Contd…
• Inferior border
– Formed mainly by the right
ventricle with small
contribution from the left
ventricle near the apex
• Left border
– ill defined and rounded
– formed by the left ventricle
partly by the left auricle.
20. Surfaces of the heart
Sternocostal surface
Formed mainly by the right
atrium and right ventricle
and partly by left ventricle
and left auricle
Left surface
Formed mainly by the left
ventricle and upper part by
left atrium and left auricle
Upper part of this surface is
crossed by the coronary
sulcus
21. Diaphragmatic surface
Formed mainly by the
left ventricle (2/3rd) an
partly by right ventricle
(1/3rd)
Rest on the central
tendon of the diaphragm
and on a small area of
the left muscular part of
the diaphragm
22. Grooves or sulci
• The division of the heart into four chambers produces
boudaries that are visible externally as grooves (sulci)
• They are
– Atrioventricular groove or coronary sulcus
– Interatrial groove
– Interventricular groove
23. Atrioventricular groove or coronary sulcus
• Separates atria from ventricles
• Forms a C-shaped curve
• Divided into anterior and posterior parts
– Anterior part consists of right and left halves
• right part: runs downwards and to the right between right atrium (and its
auricle) and right ventricle
• Left part: intervenes between left auricle and ventricle
– Posterior part:
• Intervenes between the base and diaphragmatic surface of heart
24. Contd…
• Interatrial groove
– Faintly visible posteriorly
– While anteriorly it is hidden by the aorta and pulmonary
trunk
• Interventricular groove: consists of anterior and posterior part
• Crux of the heart: meeting point of interatrial groove,
posterior interventricular groove and posterior part of
atrioventricular groove
28. Interior of right atrium
• Has a cavity and a small
out pouching called auricle
• Sulcus terminalis
(externally) – crista
terminalis (internally)
• Divides atrium into two
parts
– Smooth part /sinus venarum
behind
– Rough part in front
• Musculi pectinati
29. Openings
• Superior venacavae
opens at upper end and
has no valve
• Inferior venacavae
– opens into the lowest
part
– opening guarded by flap
like rudimentary valve
called Eustachian valve.
• Coronary sinus
– opens between opening
of inferior venacava and
AV orifice
– semicircular valve called
Thebesias valve.
– Drains most of the blood
from heart wall
• Foramina venarum
minimarum
30.
31. Interatrial septum
• Separates right and
left atrium
• Right side of interatrial
septum presents:
• Fossa ovalis –
• Limbus/annulus fossa
ovalis –
• Triangle of Koch
32. Interior of right ventricle
• Communications
– Right atrium – Atrioventricular orifice
– Pulmonary trunk – pulmonary orifice
• Wall – much thicker than atrium
• Consist of two parts
– inflowing rough part
– Outflowing smooth part
• seperated by supraventricular crest (infundibular
crest).
33. Inflowing part
• rough due to presence of irregular muscular
ridges called trabeculae carnae
• 3 types
• Ridges:- Fixed elevations
• Bridges:- having 2 fixed ends but free centers
– Moderator band / septomarginal trabeculae
• Pillar (papillary muscles):-
34. Contd..
• Papillary muscle
– Projects inward into the cavity
– Base attached to the wall
– At apex – fibrous chords – chorda tendineae – cusps
of tricuspid valves
• Tricuspid valves
– Guards AV orifice
– 3 in number – anterior, septal and posterior
– Base attached to fibrous ring
– Free edges are serrated
35.
36. Cont….
• Outflowing part/ infundibulum / conous arteriorus
– smooth and forms the upper conical part of right ventricle
– give rise to pulmonary trunk.
• Pulmonary orifice
– Guarded by 3 semilunar cusps
– No papillar muscles, no corda tendinae
38. Interior of left atrium
• Most of the wall is smooth.
• A network of musculi pectinati
is found within the left auricle.
• Posterior wall receives the
opening of four pulmonary
veins.
• Anterior wall is formed by
interatrial septum.
• Septal wall shows fossa lunate
corresponding to the fossa
ovalis of right atrium.
39. Interior of left ventricle
• Wall 3 times thicker than
right ventricle
• Interior consists of inflow
& outflow tract
Inflow tract(ventricle
proper):
• is lower rough part with
trabeculae carneae.
• Has two papillary muscle
i.e. anterior and posterior.
40. Outflow tract/aortic vestibule:
– It is upper smooth part
– Ejects blood to ascending aorta.
• two orifice i.e. left atrioventricular or bicuspid or mitral orifice
and aortic orifice.
41. Skeleton of the heart
• Fibrous ring at the
base of the ventricles
surrounding the
atrioventricular, aortic
& pulmonary orifice
• Functions:
• Provides attachment of
the cardiac muscle
• Keep the cardiac valve
competent
42. Valves of heart
• Two pairs of valves in the heart
• A pair of atriventricular valve
– Tricuspid and mitral
• A pair of semilunar valve
43. Innervation of the Heart
• Innervated by the
autonomic nervous system.
• Consists of both
sympathetic and
parasympathetic
components.
– referred to as the cardiac
plexus
44. Sympathetic Innervation
• Sympathetic innervation increases the rate
and the force of heart contractions
• arises from upper four or five thoracic
segments of spinal cord
• enter sympathetic trunk, ascend and pass
through ganglia
• travel through heart via cardiac nerves
45.
46. Parasympathetic innervation
• Parasympathetic innervation decreases heart
rate and cause constriction of the coronary
arteries
• comes off of the medulla oblongata
• via right and left vagus nerves (CN X)
