Heart
Position
External
morphology
Relations
Cardiac chambers
Conduction
Vessels
Pericardium
Position
• Lies within the
pericardium in middle
mediastinum
• Behind the body of
sternum and coastal
cartilages 2 to 6
• In front of thoracic
vertebrae 5 to 8
• A third of it lies to the
right of median plan and
2/3 to the left
External
morphology
one apex,
one base,
two surfaces
three borders
three grooves
the apex
formed by the left ventricle
the base
faces backward,upward and to the
right. Formed mainly by the left atrium and
partly by the right atrium.
two surfaces: sternocostal and diaphragmatic
surfaces
three borders: right,left and inferior borders
*the cardiac apecal incisure is on the
inferior border and right to the apex
*atrioventricular crux is a point of the
coronary and posterior interventricular grooves.
It is a important superficial mark
three grooves: coronary groove
ant. interventricular groove
post. interventricular groove
Chambers
• right atrium
• right ventricle
• left atrium
• left ventricle
—two parts(divided by the terminal crest)
ant.part atrium proper
post.part sinus
*four openings
orifice of the sup.vena cava
orifice of the inf.vena cava
inlet
orifice of the coronary sinus
the right atrioventricular orifice---outlet
*the fossa ovalis (oval foramen)
*the triangle of Kock
(tricuspid valves , orifice of the coronary sinus, tendon of todaro)
Atrioventricular node is located in.
Right ventricle

inflow tracts
 outflow tracts
(divided by the
supraventricular
crest)
 pulmonary
valve
tricuspid
valves
chordae
tendineae
papillary
muscles(3 group
Left atrium
left auricle
—five openings
*four orifices of
the pulmonary
veins
*the left
atrioventricular
orifice
Left ventricle
inflow and
outflow tracts
(divided by the
ant.cusp of
the bicuspid
valves)
※
the papillary muscles(2 groups)
structure
the walls of the heart
3 layers
—endocardium
*continue with the lining
of the large blood vessels
—myocardium
*2 kinds: the ordinary
cardiac muscles
the specially m.
— epicardium
• Septum
interatrial septum
----Oval fossa
interventricular septum
----Membranous part
Conduction System
It is consists of the special
cardiac muscles
5 parts:
sinoatrial node
atrioventricular node,
atrio-ventricular bundle
Left and right branches
Purkinje fibers.
—The sinoatrial node(SAN)
*It is lies the junction between the
right auricle and the sup.vena cava
—The atrioventricular node(AVN)
*It is lies in the lower
portion of the interatrial
septum just above the
orifice of the coronary
sinus
—Purkinje fibers
The vessels of
the heart
The arteries
—the right coronary a.
*arise from the right aortic sinus and runs along th
e right portion of the coronary groove
*2 branches: post.interventricular branch
post.branch of the left venticle
*To supply right atrium,right ventricle
post.1/3 of the interventricular septum,the
diaphragmatic surface of left ventricle,the
SAN and AVN.
—The left coronary a.
*arises from the left aortic sinus
*2 branches: ant.interventricular br.
circumflex br.
*To supply the left atrium,left ventricle,the ant. sur
face of the right ventricle,ant.2/3 of the interven
tricular septum,sometimes, supply the
SAN and AVN.
2. The veins of the heart
—The coronary sinus
*It lies in the post.portion of the coronary
sulcus between the left atrium and left
ventricle
*It opens into the right atrium
*It receives:
**the great cardiac v.
**the middle cardiac v.
**small cardiac v.
—the other veins opening into the right atrium
directly
*the ant. cardiac v.
*the smallest v.
Pericardium
1. It comprises 2 sacs:
—the fibrous pericardium
—the serous pericardium:
*parietal layer
*visceral layer
2.The pericardial cavity:
—the transverse sinus
—the oblique sinus
Pericardium sinus
•
•
Transverse sinus of pericardium－posterior to ascending
aorta and pulmonary trunk, anterior to superior vena cava and
left atrium.
Oblique sinus of pericardium－cul-de-sac , posterior to
heart, bounded by pulmonary veins on either side