Download left border of heart

SEMESTER 5 – WEEK 1
CARDIOVASCULAR MODULE
ANATOMY
TOPOGRAPHIC ANATOMY AND BLOOD SUPPLY OF THE HEART
LEARNING OBJECTIVES
At the end of class student should be able to
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Discuss position of the heart
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Discuss surface anatomy of the heart
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Know the borders and surfaces of heart
Know the blood supply of the heart
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The heart is muscular pump.
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Responsible for blood circulation.
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It is an organ with four chambers two atria and two
ventricles
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Atria receives blood.
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Ventricle propels blood to lungs and rest of body
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Long axis of heart is lies obliquely (to the left i.e. apex).
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Right sided chambers are anterior to their left sided
counter parts.
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Atria are to the right of ventricles.
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One third of the heart lies on the right of the midline
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It has right, inferior and left borders.
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It has anterior or sternocostal surface, inferior or diaphragmatic
surface, base or posterior surface and apex
BORDERS OF THE HEART
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RIGHT BORDER OF THE HEART
Consists entirely of right atrium
INFERIOR BORDER OF THE HEART
Mostly of right ventricle with small portion of left ventricle
LEFT BORDER OF HEART
Mostly left ventricle with auricle of the left atrium forms upper most part
APEX OF THE HEART
At the junction of inferior and left borders
SURFACES OF THE HEART
ANTERIOR OR INTERCOSTAL SURFACE OF THE HEART
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Consists right ventricle with right atrium on its right side and
narrow strip of the left ventricle on its left border
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INFERIOR OR DIAPHRAGMATIC SURFACE
One third left ventricle separated by posterior interventricular branch of
coronary artery
POSTERIOR SURFACE OR BASE
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Entirely of left atrium receiving the four pulmonary veins
THE RIGHT ATRIUM
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Lies between superior and vena cava
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Forms right border of heart
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Its upper part is prolonged to left of superior vena cava as right
auricle
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From angle between superior vena cava and right auricle is sulcus
terminalis internal to it is crista terminalis
THE RIGHT ATRIUM
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Between the crista and blind extremity of auricle is rough area
produced by pectinate muscles it is true auricular chamber.
Smooth walled part is produced by incorporation of the right
horn of sinus venosus
THE RIGHT ATRIUM
Opening of vena cava have small cresenteric ridge the remains
of its valve continued upwards towards the opening of coronary
sinus
The interatrial septum:
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Forms posterior wall
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Towards its lower part is fossa ovalis (its upper margin is called limbus
which is lower edge of secondary septum)
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RIGHT VENTRICLE
Projects from the left of right atrium
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Atrioventricular groove is nearly vertical on anterior surface
and anteroposterior on the diaphragmatic surface
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Lodges right coronary artery
RIGHT VENTRICLE
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Inside its walls are thrown into muscular ridges the trabecullae carnae
which projects into the cavity of ventricle
One of the ridges has broken free and lies in the cavity attached by its
two ends to the interventricular septum and papillary muscle it is called
septimarginal trabeculae or modurator band.
Papillary muscles are attached one end to the wall and other to the
cusps of tricuspid wall
RIGHT VENTRICLE
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Tricuspid valve admits three fingers
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Cusps are anterior, posterior and septal
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Edges of cusps receive cordae tendaneae (tendenous cords from
papillary muscle)
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Cavity of the ventricle continues upwards into a narrow funnel shaped
thin walled part called the infundabulum or conus
LEFT ATRIUM
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Forms base of the heart
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Lies behind the right atrium
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From it left ventricle slopes to the apex
LEFT ATRIUM
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Left auricle projects from its upper border and curves round to the front
on the left side of infundabulum (this part is rough)
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Mitral valve admits tips of two fingers and has anterior and posterior
cusp
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Anterior cusp lies between mitral and aortic orifice
LEFT VENTRICLE
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Walls of the cavity are three times thicker
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Trabeculae carnae are well developed
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It has two papillary muscles anterior (larger) and posterior
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Interventricular septum buldges into the caviy of right atrium
LEFT VENTRICLE
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In cross section left ventricle is circular and right ventricle is
cresenteric
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Aortic valve is guarded by aortic valve, it lower than pulmonary orifice
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Aortic and pulmonary orifice has semilunar cusps
FIBROUS SKELETON
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Atria and ventricles are attached with a pair of conjoined fibrous
rings which is in form of figure of ‘8’ bound atrioventricular orifice
Atrioventricular bundle is only communication between atria and
ventricle
Membranous part of interventricular septum is attached to the fibrous
skeleton and cusps are also attached with it
STRUCTURE OF CUSPS
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Tricuspid and mitral are flat and their edges are serrated
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In systole do not meet edge to edge but come into mutual
contact with each other
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This contact and pull of marginal trabeculae prevent evertion
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Centrally attached corda prevent balooning towards atrium
STRUCTURE OF CUSPS
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Pulmonary and aortic valves are cup shaped
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Free edge of each cusp contains a central fibrous nodule from
each of which straight edges slope at 120 degrees from each
other to the attached base of the cusp
SURFACE ANATOMY OF THE HEART
RIGHT BORDER OF THE HEART
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From lower border of the right third costal cartilage to the lower
border of the right 6th costal cartilage just beyond the right margin
of sternum.
Draw a slight curve between these points
INFERIOR BORDER
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Right 6th costal cartilage to the apex which is normally in the left
5th inter costal space in the midclavicular line
LEFT BORDER
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From the apex of the left border extends upwards to the lower
border of the left second costal cartilage about 2 cm from the
sternal margin
SURFACE MARKING OF THE VALVES OF HEART
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All valves lie behind the sternum making a line with each other
which is nearly vertical
Tricuspid and mitral valves indicated by vertical lines over lower
part of the sternum
SURFACE MARKING OF THE VALVES OF HEART
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Tricuspid valve lies behind the midline of the lower sternum and mitral
valve overlapping it lies higher and some what to the left opposite the
4th left costal cartilage.
SURFACE MARKING OF THE VALVES OF HEART
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The aortic and pulmonary orifices lie behind the left border of the
sternum at the level of third intercostal space and the third costal
cartilage respectively
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HEART SOUNDS BEST AUDIBLE
Tricuspid valve over its surface
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Mitral valve at the apex beat
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HEART SOUNDS BEST AUDIBLE
Aortic valve where ascending aorta lies near the surface at the right
sternal margin in the second intercostal space and for the pulmonary
valve at the left sternanal margin at the same level over the pulmonary
trunk
BLOOD SUPPLY OF THE HEART
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Two coronary arteries i.e. right and left coronary arteries and their
branches supply blood to the heart
Both arise from aortic sinuses.
BLOOD SUPPLY OF THE HEART
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Aortic sinuses arise from the beginning of ascending aorta
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RIGHT CORONARY ARTERY
Arise from anterior aortic sinus
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Passes between right auricle and infundabulum of right ventricle
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Run in the atrioventricular groove
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At inferior border of heart turns backwards and runs posteriorly
BRANCHES OF RIGHT CORONARY ARTERY
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Conus artery passes upwards and medially on the front of the
Conus of the right ventricle, It anastomosis around the origin of
pulmonary trunk with the similar branch from left coronary artery
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SA.nodal artery (arises from 60% of cases from right and 40% from
left coronary) passes backwards between right auricle and the aorta
and forms a vascular ring around the inferior vena cava
BRANCHES OF RIGHT CORONARY ARTERY
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Right marginal artery: Arises at the inferior border passes to the
left along the right ventricle
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Posterior interventricular branch (posterior descending artery)
Arise on diaphragmatic surface. This large vessel passes along the
interventricular groove towards the apex of the heart
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Right coronary artery has a characteristic loop where posterior
interventricular artery is given off here AV nodal artery is given off.
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AV nodal artery
Left ventricular branches
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Coronary artery becomes smaller and anastomosis with termination of
circumflex branch of left coronary artery
LEFT CORONARY ARTERY
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Arises from left posterior aortic sinus
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Behind the pulmonary trunk the vessel emerges between the left
auricle and the infundabulum of right ventricle
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It divides into two terminal branches i.e. circumflex and anterior
interventricular branch
BRANCHES OF LEFT CORONARY ARTERY
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Circumflex branch continues along the left margin to the back of
heart in atrioventricular groove and anastomosis with right coronary
artery
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Branches of circumflex branch
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Left marginal artery
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40% SA nodal artery passes to right behind the ascending aorta
BRANCHES OF LEFT CORONARY ARTERY
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Anterior interventricular artery left anterior descending artery
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Most often affected by disease
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Runs downwards in the atrioventricular groove to anastomose under
the apex with posterior interventricular branch of right coronary artery
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Branches anterior interventricular artery
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Left conus artery
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Diagonal branch
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Several ventricular branches
LEFT DOMINENCE
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In 10% of cases right coronary is shorter and posterior interventricular
artery is replaced by continuation of circumflex artery which also
supplies AV node
Anastomosis at arteriolar level exists between termination of right and
left coronary arteries in the atrioventricular groove and between
interventricular and Conus branches
Potential anastomosis exists between coronary arteries and pericardial
arteries around the root of the great vessel
Time factor of occlusion is important
VENOUS DRAINAGE
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Veins of the heart are coronary sinus and its five tributaries i.e.
Great cardiac vein
Middle cardiac vein
Small cardiac vein
Oblique vein of left atrium
Anterior cardiac veins
CORONARY SINUS
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Coronary sinus receives most of blood is wide vessel and lies in the
posterior part of the interventricular groove and is covered by thin layer
of myocardium
Opens at its right end into the posterior wall of the right atrium to
the left of inferior vena caval opening
Great cardiac veins
Accompanies anterior interventricular and circumflex arteries an d
enters to the left of sinus
Receives number of ventricular tributaries
CORONARY SINUS
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Middle cardiac vein
Accompanies the posterior interventricular artery and opens near the
termination of the coronary sinus
Small cardiac veins
Opens into the lower end of coronary sinus near its arterial end
Posterior vein of the left ventricle joins the sinus to the left of middle
cardiac vein
Oblique vein of the left ventricle runs downwards into the sinus near
its left end
CORONARY SINUS
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Anterior cardiac veins
Are a series of parallel veins that run across the surface of the ventricle
to open into the right atrium
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The right marginal vein passes to the right along the inferior cardiac
margin and joins the small cardiac vein or drains directly in to the right
atrium in the manner of anterior cardiac vein
Venae cordis minimae are very small veins in the walls of four
chambers of the heart that opens directly into the respective chambers
they are most frequently in the right atrium
THE END