Transcript 17-Heart

By
Prof.
Saeed Abuel Makarem
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Pericardium
A fibro-serous sac
Surrounds the heart &
proximal part of its great
vessels (Aorta, Pulmonary
artery, SVC, IVC, & 4
pulmonary veins)
Formed of:
Outer fibrous layer
Inner serous sac
Serous sac has 2 layers:
Parietal & Visceral
(epicardium)
Fibrous Pericardium
• Conical or flask shape
• Apex: directed upwards fused
with adventitia of 3 big vessels
• Base: rests on diaphragm
• Fuses with central tendon of
diaphragm.
• Posteriorly: Separated by post.
Mediasinum from middle four
thoracic vertebrae (5 to 8)
• Anteriorly: body of sternum,
costal cartilages from 2 to 6, ant.
Border of lung & pleura, remains
of thymus gland & two Sternopericardial ligaments
• Extends from 2nd to 6th rib
Located in the middle
mediastinum
posterior to the
body of sternum
and 2nd-6th
costal
cartilages
Anterior to T5-T8
vertebrae
1-1.5 cm to the
right of the
sternum
5-7.5 cm to the
left of median
plane at the level
of 5th intercostal
space
Function of serous pericardium:
• 1- Lubrication to prevent friction
• 2- Prevent adhesion of the heart to its surrounding
Function of fibrous pericardium
1- Maintain the central position of the
heart
2-Keeps large vessels open
3-Helps venous return
4-Acts as a wall for the serous
pericardium.
5- Prevents over loading &
overdistention of the heart
Serous pericardium
Serous sac that has been
invaginated by developing heart in
the fetal life
Visceral layer: Epicardium.
Parietal layer: Lines the fibrous
pericardium
Pericardial cavity: potential space.
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Sinuses of pericardium
2 sinuses in the serous
pericardium are formed
during development of the
heart (Transverse & Oblique)
• Transverse sinus
A recess behind pulmonary
trunk & ascending aorta
Boundaries:
Ant: Pulmonary trunk &
ascending aorta.
Post: SVC &Upper part of
the 2 atria
Above: Rt. Pulmonary artery
Below: the 2 atria mainly Lt.
• Oblique sinus
• It separates the base of heart
(left atrium) from posterior
mediastinum (descending
aorta & esophagus)
• Boundaries:
• Ant: back of Lt. atrium
• Post: fibrous pericardium &
posterior mediastinum
(esophagus & descending
aorta )
• Left: 2 Left pulmonary veins
• Right: 2 right pulmonary veins
& IVC
Blood Supply
Arterial Supply:
Mainly supplied by pericardiophrenic and
musculophrenic arteries, branches of internal
thoracic
Also supplied by pericardial branches of bronchial,
esophageal and superior phrenic arteries
Visceral layer of the serous pericardium
(epicardium) supplied by the branches of the
coronary arteries
Venous drainage: Veins are tributaries of azygos
system.
Pericardiophrenic veins also drain into the internal
thoracic vein
Nerve Supply
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 innervated by (autonomic fibers)
branches of the sympathetic trunks and
the vagus nerves
Heart
• Muscular pump that keeps
circulation going on.
• It is the size of hand’s fist of
the same person
• 2/3 of its breadth lies to left of
median plane and 1/3 right to
median plane
• It is conical in shape having
an apex, base,
• Sterno-costal, diaphragmatic,
surfaces
• and right, and left borders.
External Features: Surfaces
The heart has:
Sternocostal (Anterior) surface
Diaphragmatic (Inferior) surface
Base (Posterior surface)
Apex
Apex
• Directed downwards,
forwards & to left
• Lies in LT. 5th
Intercostal space 3 & ½
inches ( 9 cm) from
median plane.
• Formed only by LT.
ventricle.
• Pericardium &
diaphragm separate the
apex from fundus of
stomach
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Base
Directed backwards and
slightly to right.
Formed by 2 atria mainly
the left atrium.
Separated from post
Mediastinum by oblique
sinus of pericardium
Lies opposite middle 4
thoracic vertebrae (5 to 8)
Bounded inferiorly by
coronary groove that lodge
the coronary sinus.
Sternocostal surface
*Sterno-costal surface
• Lies behind body of sternum &
3rd to 6th costal cartilages.
• Divided by coronary groove into:
• Atrial part: Rt. Atrium
• Ventricular part: the two
ventricles, mainly Rt.
• Borders:
• Upper: Straight, formed by the 2
atria but concealed by the
ascending aorta & pulmonary
trunk.
• Lower: Concave formed by Rt.
Ventricle & small apical part of Lt
ventricle
• Rt.: Convex formed by Rt. Atrium
• Lt.: Convex ,formed by Lt. auricle
and Lt. ventricle.
Diaphragmatic surface
• Left 2/3 of this surface
are formed by Lt ventricle
• Rt. 1/3 is formed by Rt.
Ventricle
• The 2 ventricles are
separated by post.
Interventricular groove.
The groove lodges the post.
Interventricular artery &
middle cardiac vein
Surface anatomy of Heart
• Point 1: Lower border of 2nd Lt
costal cartilage one & half
inches from the median plane.
• Point 2: Upper border of Rt. 3rd
costal cartilage one inch from
median plane.
• Point 3: Upper border of Rt. 6th
costal cartilage one inch from
its junction with the sternum.
• Point 4: Apex Lt. 5th Intercostal
space 3 ½ inches from median
plane.
Surface anatomy of
the valves
Pulmonary: Left 3rd
sternocostal junction
Aortic: Left 3rd
Intercostal space just
left to sternum
Mitral: Left 4th
sternocostal junction
Tricuspid: 4th
Intercostal space
near the middle line.
Surface
anatomy
Auscultation of the cardiac valves
A
Arterial Supply
It is supplied by right & left
coronary arteries
Coronary arteries arise from
the ascending aorta
immediately above the
aortic valves
Coronary arteries and their
branches are distributed
over the surface of the
heart lying within the
subepicardial connective
tissue
Right Coronary Artery
Arises from anterior sinus of
ascending aorta
Runs between the pulmonary
trunk and right auricle
Runs in the atrioventricular
groove
At the inferior border of the
heart it turns posteriorly in
the atrioventricular groove
Anastomosis with a branch
from the left coronary artery
in the posterior
interventricular groove
Right Coronary Artery: Branches
1-Right conus artery
2-Anterior ventricular
branches: 2-3 in number,
3-Marginal branch
4-Posterior ventricular
branches, which gives a
branch to atrioventricular
node
6-Posterior
interventricular artery
7-Atrial branches, & artery of
the sinuatrial node which
also supplies atria
Left Coronary Artery
Larger than the right
Supplies major part of the
heart
Arises from the left
posterior aortic sinus
Runs between the
pulmonary trunk and left
auricle
Runs in the atrioventricular
groove
Divides into anterior
interventricular &
circumflex branches
Left Coronary Artery: Branches
Anterior interventricular
artery, which gives a
small conus artery
Circumflex artery, gives:
Left marginal
Anterior
ventricular
Posterior
ventricular
Atrial branches
Coronary Artery Anastomoses
Although anastomosis do exist between
the terminal branches of the right and
left coronary arteries,
But these are not large enough to
compensate for any sudden blockage
of a large branch.
A sudden blockage of the larger
branches results in myocardial
infarction.
Venous Drainage of the Heart
Most of the blood drains into the right
atrium through the coronary
sinus.
Coronary sinus:
Lies in the posterior part of the
atrioventricular
It is the continuation of the great
cardiac vein
Opens into the right atrium to the left
of the inferior vena cava
Tributaries: small and middle
cardiac veins, posterior vein of the
left ventricle, oblique vein of the
left atrium
Anterior cardiac veins drain directly
into the right atrium
Vena cordis minimi open directly into
heart chambers
anterior