 Base of heart is base because of

THE HEART the pyramidal shape

 Hollow  Base lies opposite to apex
 Muscular  Heart doesn’t rest on the base it
 Somewhat pyramidal rests on diaphragmatic surface
 In pericardium in the mediastinum
 Connected at base to great blood
vessels
 Or else lies free within the
pericardium
 Has 3 surfaces;
1. Sternocostal / anterior
Formed by ;
right atrium
right ventricle
separated by
atrioventricular groove and
small part of left ventricle
and left auricle
2. Diaphragmatic / inferior
Formed by;
Right ventricle
Left ventricle
Separated by posterior Boundaries of the heart
interventricular groove
And part of inferior surface I. Right boundary
of right atrium where Formed by superior vena cava and right
inferior vena cava open atrium
3. Base / posterior
Formed by; Passes archedly from superior margin of
Left atrium (4 pulmonary the 3rd coastal cartilage to inferior margin
veins open here) of 5th coastal
Small part of right atrium 2 – 2.5 cm laterally from right sternal line
 Apex
Formed by left ventricle
 It is directed downward, forward II. Inferior boundary
and to the left
Formed by right ventricle and small part of
 Lies at the level of 5th left
left ventricle
intercoastal space
 1.5 – 2 cm medially from Passes from inferior margin of 5th coastal
midclavicular line cartilage obliquely to left and downward to
 In region of apex, apex beat is seen 5th intercoastal space between right
and palpated in living subject parasternal line and left midclavicular line
  Coronary arteries arise from aorta
immediately above aortic valve
III. Left boundary
 Right coronary artery arises from
Formed by left ventricle, left auricle , anterior aortic sinus of ascending
pulmonary artery, arch of aorta aorta
 Runs forward between pulmonary
Passes upwards from 5th intercoastal space
trunk and right auricle
1.5 – 2 cm medially from the left  Descends in atrioventricular groove
midclavicular archedly to the 3rd rib and with the small cardiac vein giving
rises upwards to the 2nd intercoastal space branches to the right atrium and
at the space distance of 2 cm from right right ventricle
sternal line

 Inferior border of heart small

cardiac vein continues posteriorly
along the atrioventricular groove to
anastomose with left coronary
artery
 Gives off a marginal branch that
supplies the right ventricle and a
posterior interventricular branch
that supplies both ventricles
 Posterior interventricular branch
anastomoses with anterior
interventricular branch of the left
coronary artery in the posterior
Skelletotopy of heart valves interventricular groove
 Tricuspid valve is behind right half  Left coronary artery is larger than
of sternum opposite the 4th right coronary artery
intercoastal space  LCA arises from left posterior aortic
 Mitral valve is behind left half of sinus of ascending aorta
sternum opposite the 4th coastal  Passes forward between the
cartilage pulmonary trunk and left auricle
 Pulmonary valve is behind the  Enters atrioventricular groove and
medial end of 3rd and adjoining divides into an anterior
part of the sternum interventricular branch and a
 Aortic valves are behind left half of circumflex branch
the sternum opposite the 3rd  anterior interventricular branch
intercoastal space runs downward to the apex of the
 Arterial supply of heart is by right heart in the anterior
and left coronary arteries interventricular groove together
with the great cardiac vein.
  It then passes around the apex Passes downwards to end in the
anastomose with the posterior right atrium of the heart
interventricular branch of the right Azygous vein joins the posterior
coronary artery. aspect of the superior vena cava
 The anterior interventricular just before it enters the
branch supplies the right and left pericardium
ventricles and the ventricular
septum.
 The circumflex branch follows the  The ascending aorta
atrioventricular groove, winds Found into the pericardial cavity
around the left margin of the heart Beginning of the ascending aorta is
and ends by anastomosing with the covered anteriorly on the left by
right coronary artery. pulmonary trunk and anteriorly on
 The circumflex branch supplies the the right by the right auricle
left atrium and the left ventricle. Right pulmonary artery is found
 Although anastomoses between posterior to the ascending aorta
the terminal branches of the
coronary arteries do 0d one are not
large enough to provide an  The arch of aorta has the oblique
adequate supply of blood to direction from the right to the left
cardiac muscle should one of the and from the front backwards.
larger branches become blocked by  The beginning of the arch is
disease. covered by the right pleural sac
 Most of the blood from the heart and final part of the arch is covered
wall drains into the right atrium by by the left pleural sac.
means of the coronary sinus  The middle part of the arch is
 This lies in the posterior part of the covered by the thymus.
atrioventricular groove and is a  The trachea, oesophagus, thoracic
continuation of the great cardiac and left recurrent nerve lie
vein posterior to the arch of the aorta.
 It opens into the right atrium to the  The left vagus nerve laterally and
left of the inferior vena cava the left phrenic nerve anteriorly
and medially cross the arch of the
Nerve supply
aorta in the front.
 By sympathetic and  The left brachiocephalic vein
parasympathetic fibres of ANS via passes above and anterior to the
cardiac plexuses arch of the aorta.
 The superior vena cava  The part of the aorta between the
Contains all venous blood from arch of aorta and descending aorta
head and neck and both upper is called isthmus of the aorta.
limbs and is formed by union of  The pulmonary trunk is found on
brachiocephalic veins the left and anterior to the
ascending aorta.
 Under the arch of the aorta the
pulmonary trunk is divided into two
pulmonary arteries: right and left.
 The ligamentum arteriosum is
found between the arch of the
aorta and the bifurcation of the
pulmonary trunk.
 Pulmonary trunk.
The pulmonary trunk conveys
deoxygenated blood from the right
ventricle of the heart to the lungs.
 It leaves the upper part of the right
ventricle and runs upward,
backward, to the left.
 Terminates in the concavity of the
aortic arch and divides into right
and left pulmonary arteries.

 Pulmonary veins. Two pulmonary

veins leave each lung carrying
oxygenated blood to left atrium of
the heart