Download Clinical Anatomy of Pericardium and Heart part 2

Clinical Anatomy of Heart
Lecture 2
Associate Professor
Dr. Alexey Podcheko
SJSM
Upd Fall 2014
The Heart: Groves
•Externally, the atria are demarcated from the ventricles by the
coronary or atrioventricular groove (sulcus)
•The right and left ventricles are demarcated from each other by
anterior and posterior interventricular (IV) grooves
The Heart: Surface Anatomy
The heart is shaped like a tilted pyramid with an apex (directed
anteriorly and to the left), a base (opposite the apex, facing
mostly posteriorly), four surfaces and four borders
The Heart: Apex
•Is formed by the inferolateral part of the left ventricle.
•Lies posterior to the left 5th intercostal space in adults
•Is where the sounds of mitral valve closure are maximal (apex beat)
•The apex underlies the site where the heartbeat may be auscultated on
the thoracic wall.
The Heart: Base
•Is the heart's posterior aspect
(opposite the apex).
•Is formed mainly by the left atrium, with
a lesser contribution by the right atrium.
•Faces posteriorly toward the bodies of
vertebrae T6 - T9 and is separated from
them by the pericardium, oblique
pericardial sinus, esophagus, and aorta.
•Extends superiorly to the bifurcation of
the pulmonary trunk and inferiorly to
the coronary groove.
•Receives the pulmonary veins on the
right and left sides of its left atrial
portion and the superior and inferior
venae cavae at the superior and inferior
ends of its right atrial portion.
The Heart: Surfaces (1/4)
•Anterior (sternocostal) surface, formed mainly by the right
ventricle.
The Heart: Surfaces (2/4)
Diaphragmatic (inferior)
surface, formed mainly by
the left ventricle and partly
by the right ventricle; it is
related mainly to the
central tendon of the
diaphragm.
The Heart: Surfaces (3/4)
Right pulmonary surface, formed mainly by the right atrium.
The Heart: Surfaces (4/4)
Left pulmonary surface,
formed mainly by the left
ventricle; it forms the cardiac
impression of the left lung.
The Heart: Borders (1/4)
Right border (slightly convex), formed by the right atrium and
extending between the superior vena cava and the inferior vena
cava
Anterior view
Posterior view
The Heart: Borders (2/4)
•Inferior border (oblique, nearly vertical), formed mainly by the
right ventricle and slightly by the left ventricle.
Anterior view
Posterior view
The Heart: Borders (3/4)
Left border (nearly horizontal), formed mainly by the left ventricle
and slightly by the left auricle.
The Heart: Borders (4/4)
•Superior border, formed by the right and left atria and
auricles in an anterior view; the ascending aorta and
pulmonary trunk emerge from this border and the superior
vena cava enters its right side.
•Posterior to the aorta and pulmonary trunk this border forms
the
inferior boundary of the transverse pericardial sinus
.
Clinical Correlates: Positional Abnormalities
of the Heart
•Abnormal folding of the embryonic heart may cause the position of
the heart to be completely reversed so that the apex is directed to
the right instead of the left – dextrocardia.
•This congenital anomaly is the most common positional
abnormality of the heart, but it is still relatively uncommon
•Dextrocardia
is associated with mirror image positioning of the
.
great vessels and the arch of the aorta.
CXR showing dextrocardia and right sided stomach – Situs inversus
Clinical Correlates: Positional Abnormalities
of the Heart
•This anomaly may be part of a general transposition of the thoracic
and abdominal viscera (situs inversus), or the transposition may
affect only the heart (isolated dextrocardia).
•In dextrocardia with situs inversus, the incidence of accompanying
cardiac defects is low, and the heart usually functions normally.
•In isolated dextrocardia, however, the congenital anomaly is
complicated by severe cardiac anomalies, such as transposition of
the great arteries.
CXR showing dextrocardia and left sided stomach – Isolated dextrocordia
Anatomy of the Right Atrium
•The right atrium receives
blood from the superior
vena cava, inferior vena
cava, and coronary sinus.
•The ear-like right auricle
is a conical muscular
pouch that projects from
this chamber
•Walls of the Right
Atrium:
A. Posterior wall formed
by superior vena cava
and inferior vena cava
and coronary sinus
opening, it has smooth
surface and called sinus
venarum
B. Anterior wall composed of pectinate muscles and has rough surface.
•The smooth and rough parts of the atrial wall are separated externally by a
shallow terminal groove, and internally by a vertical ridge, the crista terminalis.
Anatomy of the Right Atrium
The interatrial septum separating the atria has an oval,
thumbprint-size depression, the oval fossa (fossa ovalis), which is
a remnant of the oval foramen (foramen ovale) and its valve in
the fetus.
Anatomy of the Right Atrium: Electrical conduction
system
:Specialized cardiac muscle
cells that carry impulses
throughout the heart
musculature, signaling the
chambers to contract in the
proper sequence
Main parts of conduction
system:
1. Sinoatrial node
2. Atrioventricular Node
3. Bundle of His
4. Left/Right Branches of the
bundle of His
5. Purkinje fibers
Anatomy of the Right Atrium: SA, AV nodes
Conduction system
 SA node (sinoatrial)
 In wall of RA
 Sets basic rate: 70-
80bpm
 Is the normal pacemaker
 Impulse from SA to atria
 Impulse also to AV node
via internodal pathway
 AV node
 In interatrial septum
Conduction continued
 SA node through AV
bundle (bundle of His)
 Into interventricular
septum
 Divides
R and L bundle branches
become subendocardial
branches (“Purkinje
fibers”)
 Contraction of
ventricles begins at
apex!!!
ECG – recording of electric activity of the heart
12 lead EKG
HEART- Clinical Note
 Damage to the conducting system causes a heart block,
which interferes with the ability of the ventricles to
receive the atrial impulses.
 A delay or disruption of the electrical signals produces an
irregular and slower heartbeat, reducing the heart’s
efficiency in maintaining adequate circulation.
 Heart block requires a pacemaker to be implanted.
 Atrial or ventricular fibrillation is a cardiac arrhythmia
resulting from rapid irregular uncoordinated contractions
of the atrial or ventricular muscle due to fast repetitive
excitation of myocardial fibers, causing palpitations,
shortness of breath, angina, fatigue, congestive heart
failure, and sudden cardiac death.
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HEART: Left Atrium
 Is smaller and has thicker walls than the right atrium, but its walls are
smooth, except for a few pectinate muscles in the auricle.
 Is the most posterior of the four chambers lying posterior to the right
atrium but anterior to the esophagus
 shows no structural borders on a posteroanterior radiograph.
 Receives oxygenated blood through four pulmonary veins.
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HEART: Right Ventricle
Makes up the major portion of the anterior (sternocostal) surface of
the heart. Contains the following structures:
1. Trabeculae Carneae Cordis

Are anastomosing muscular ridges of myocardium in the
ventricles.
2. Papillary Muscles

Are cone-shaped muscles enveloped by endocardium.

Extend from the anterior and posterior ventricular walls and
the septum, and their apices are attached to the chordae
tendineae.

Contract to tighten the chordae tendineae, preventing the cusps
of the tricuspid valve from being everted into the atrium by the
pressure developed by the pumping action of the heart. This
prevents regurgitation of ventricular blood into the right
atrium.

There are 3 papillary muscles – anterior, posterior and
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septal.
HEART: Right Ventricle
3. Chordae Tendineae
 Extend from one papillary muscle to more than one cusp of the tricuspid valve.
 Prevent eversion of the valve cusps into the atrium during ventricular contractions.
4. Conus Arteriosus (Infundibulum)
 Is the upper smooth-walled portion of the right ventricle, which leads to the
pulmonary trunk.
5. Septomarginal Trabecula (Moderator Band)
 Is an isolated band of trabeculae carneae that forms a bridge between the
intraventricular (IV) septum and the base of the anterior papillary muscle of the
anterior wall of the right ventricle.
 Is called the moderator band for its ability to prevent overdistention of the
ventricle and carries the right limb (Purkinje fibers) of the atrioventricular (AV)
bundle from the septum to the sternocostal wall of the ventricle.
6. IV Septum
 Is the place of origin of the septal papillary muscle.
 Is mostly muscular but has a small membranous upper part, which is a common site
of ventricular septal defects (VSDs).
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HEART: Right Ventricle
Conus Arteriosus (Infundibulum)
Papillary Muscles
Trabeculae Carneae Cordis
IV Septum
Chordae Tendineae
Septomarginal Trabecula
(Moderator Band)
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HEART: Right Ventricle
Right Ventricle
1.
Trabeculae Carneae Cordis
2.
Conus Arteriosus
(Infundibulum)
3.
Chordae Tendineae
4.
Papillary Muscles
5.
Septomarginal Trabecula
(Moderator Band)
6.
IV Septum
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HEART: Left Ventricle
Left Ventricle
 Lies at the back of the heart, and its
apex is directed downward, forward, and
to the left.

Is divided into the left ventricle proper
and the aortic vestibule, which is the
upper anterior part of the left ventricle
and leads into the aorta.

Contains two papillary muscles (anterior
and posterior) with their chordae
tendineae and a meshwork of muscular
ridges, the trabeculae carneae cordis.

Performs harder work, has a thicker (two
to three times as thick) wall, and is
longer, narrower, and more conicalshaped than the right ventricle.
Papillary
Muscles
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Chordae Tendineae
HEART Valves
Heart Valves
 Pulmonary Valve
 Lies behind the medial end of the left third costal cartilage and adjoining
part of the sternum.
 Is most audible over the left second intercostal space just lateral to the
sternum.
 Is opened by ventricular systole and shut slightly after closure of the
aortic valve.
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HEART Valves
 Aortic Valve
 Lies behind the left half of the sternum opposite the third intercostal space.
 Is closed during ventricular diastole; its closure at the beginning of
ventricular diastole causes the second (“dub”) heart sound.
 Is most audible over the right second intercostal space just lateral to the
sternum
 Nodule, Lunula, Left and right coronary sinuses
Right
Left
Coronary Coronary
sinus
sinus
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HEART Valves
 Tricuspid (Right AV) Valve
 Lies between the right atrium and ventricle, behind the right half of the
sternum opposite the fourth intercostal space, and is covered by
endocardium.
 Is most audible over the right (or left for some people) lower part of the
body of the sternum.
 Has anterior, posterior, and septal cusps, which are attached by the
chordae tendineae to three papillary muscles that keep the valve closed
against the pressure developed by the pumping action of the heart.
 Is closed during the ventricular systole (contraction); its closure
contributes to the first (“lub”) heart sound.
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HEART Valves
 Bicuspid (Left AV) Valve
 Is called the mitral valve because it is shaped like a bishop’s
miter.
 Lies between the left atrium and ventricle, behind the left half
of the sternum at the fourth costal cartilage, and has two
cusps: a larger anterior and a smaller posterior.
 Is closed slightly before the tricuspid valve by the ventricular
contraction (systole); its closure at the onset of ventricular
systole causes the first (“lub”) heart sound.
 Is most audible over the apical region of the heart in the left
fifth intercostal space at the midclavicular line.
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HEART- Clinical Note
Myocardial infarction
 is a necrosis of the myocardium because of local ischemia resulting
from vasospasm or obstruction of the blood supply, most commonly by a
thrombus or embolus in the coronary arteries. Symptoms are severe
chest pain or pressure for a prolonged period (more than 30 minutes),
congestive heart failure, and murmur of mitral regurgitation. It can be
treated with nitroglycerin (prevents coronary spasm and reduces
myocardial oxygen demand), morphine (relieves pain and anxiety),
lidocaine (reduces ventricular arrhythmias), or atropine (restores
conduction and increases heart rate).
 Angina pectoris
 is characterized by attacks of chest pain originating in the heart and
felt beneath the sternum, in many cases radiating to the left shoulder
and down the arm. It is caused by an insufficient supply of oxygen to
the heart muscle because of coronary artery disease or exertion (e.g.,
exercise, excitement) or emotion (e.g., stress, anger, frustration).
Symptoms and treatment are similar to those of myocardial infarction.
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HEART- Clinical Note
Mitral valve prolapse
 is a condition in which the valve everts into the left atrium and thus fails
to close properly when the left ventricle contracts. It may produce chest
pain, shortness of breath, palpitations, and cardiac arrhythmia. In most
cases, no treatment is needed.
Endocarditis
 is an infection of the endocardium of the heart, most commonly involving
the heart valves and is caused by a cluster of bacteria on the valves. The
valves do not receive any blood supply and white blood cells cannot enter,
and thus they have no defense mechanisms. Symptoms include fatigue,
weakness, fever, night sweats, anorexia, heart murmur, and shortness of
breath. Risk factors include a damaged abnormal heart valve, mitral valve
prolapse, and certain congenital heart defects. Cardiac murmur is a
characteristic sound generated by turbulence of blood flow through an
orifice of the heart.
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Coronary Arteries
Arise from the ascending aorta and are filled with blood during the ventricular
diastole.

44
Have maximal blood flow during diastole and minimal blood flow during systole
because of compression of the arterial branches in the myocardium during systole.
Coronary Arteries
 Right Coronary Artery
 Arises from the anterior (right) aortic sinus
of the ascending aorta, runs between the
root of the pulmonary trunk and the right
auricle, and then descends in the right
coronary sulcus, and generally supplies the
right atrium and ventricle.
 Gives rise to the following:
a) SA Nodal Artery

Passes between the right atrium and the
root of the ascending aorta, encircles
the base of the SVC, and supplies the
SA node and the right atrium.
b) Marginal Artery

Runs along the inferior border toward
the apex and supplies the inferior margin
of the right ventricle.
c) Posterior IV (Posterior Descending) Artery

Is a larger terminal branch and supplies
a part of the IV septum and left
ventricle and the AV node.
d) AV Nodal Artery
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
Arises opposite the origin of its posterior
IV artery and supplies the AV node.
Coronary Arteries
Left Coronary Artery
 Arises from the left aortic sinus of the ascending aorta, just above
the aortic semilunar valve.
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•Is shorter than the right coronary
artery and usually is distributed to
more of the myocardium.
•Gives rise to the following:
1. Anterior IV (Left Anterior
Descending= LAD) Artery,
Generally supplies anterior
aspects of the right and left
ventricles and is the chief
source of blood to the IV
septum and the apex.
2. Circumflex Artery, Runs in
the coronary sulcus, gives off
the left marginal artery,
supplies the left atrium and left
ventricle, and anastomoses
with the terminal branch of the
Dominance of the coronary arterial system
- defined by which
artery gives rise to
the posterior
interventricular (IV)
branch (posterior
descending artery).
Dominance of the right
coronary artery is
typical (approximately
67%); the right coronary
artery gives rise to the
large posterior
interventricular branch,
which descends in the
posterior
interventricular groove
toward the apex of the
heart.
Coronary Arteries
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Coronary Arteries
49
Cardiac Veins and Coronary Sinus
1. Coronary Sinus
 Is the largest vein draining the heart and lies in the coronary
sulcus, which separates the atria from the ventricles.
 Opens into the right atrium between the opening of the IVC and the
AV opening.
 Has a one-cusp valve at the right margin of its aperture.
 Receives several veins: the great, middle, and small cardiac veins; the
oblique vein of the left atrium; and the posterior vein of the left
ventricle.
 2. Great Cardiac Vein
 Begins at the apex of the heart and ascends along with the IV branch
of the left coronary artery.
 Turns to the left to lie in the coronary sulcus and continues as the
coronary sinus.
 3. Middle Cardiac Vein
 Begins at the apex of the heart and ascends in the posterior IV
groove, accompanying the posterior IV branch of the right coronary
artery.
 Drains into the right end of the coronary sinus.
Cardiac Veins , contd
4. Small Cardiac Vein
 Runs along the right margin of the heart in company with the marginal
artery and then posteriorly in the coronary sulcus to end in the right
end of the coronary sinus.
 5. Oblique Vein of the Left Atrium
 Descends to empty into the coronary sinus, near its left end.
 6. Anterior Cardiac Vein
 Drains the anterior right ventricle, crosses the coronary groove, and
ends directly in the right atrium.
 7. Smallest Cardiac Veins (Venae Cordis Minimae)
 Begin in the wall of the heart and empty directly into its chambers.
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Heart Innervation
Cardiac Plexus:
 Receives the superior, middle, and
inferior cervical and thoracic
cardiac
nerves
from
the
sympathetic trunks and vagus
nerves.
 Is divisible into the superficial
cardiac plexus, which lies beneath
the arch of the aorta in front of the
pulmonary artery, and the deep
cardiac plexus, which lies posterior
to the arch of the aorta in front of
the bifurcation of the trachea.
 Sympathetic
 Increases rate and force of
contractions
 Parasympathetic (branches of
Vagus n.)
 Slows the heart rate
HEART- Clinical Note
 Coronary atherosclerosis is characterized by the
presence of sclerotic plaques containing cholesterol
and lipoid material that impair myocardial blood flow,
leading to ischemia and myocardial infarction.
 Coronary
angioplasty
is
an
angiographic
reconstruction (radiographic view of vessels after the
injection of a radiopaque material) of a blood vessel
made by enlarging a narrowed coronary arterial lumen.
It is performed by peripheral introduction of a
balloon-tip catheter and dilation of the lumen on
withdrawal of the inflated catheter tip. A metal stent
is often placed during angioplasty.
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HEART- Clinical Note
 Coronary bypass involves a connection of a section of
vessel usually the saphenous vein or of the internal
thoracic artery or other conduit between the aorta and a
coronary artery distal to an obstruction in the coronary
artery, shunting blood from the aorta to the coronary
arteries. Alternatively, the internal thoracic artery is
connected to the coronary artery distal to the obstructive
lesion.
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