The document summarizes the cardiovascular system and its components. It describes the heart, arteries, veins, capillaries and their classifications. It discusses circulation patterns like systemic, pulmonary and portal circulation. It also covers topics like anastomoses, blood supply of arteries and veins, and clinical conditions like atherosclerosis and aneurysms.

1. Bereket s (Msc in medical Anatomy)

2. Cardiovascular system
 Cardiovascular system is the transport system of the body, through which the nutrients
are conveyed to places where these are utilized, and the metabolites (waste products) are
conveyed to appropriate places from where these are expelled.
 The conveying medium is a liquid tissue, the blood, which flows in tubular channels
,called blood vessels.
 The circulation is maintained by the central pumping organ ,called the heart.

3. COMPONENTS
 1.Heart- It is a four-chambered muscular organ
which pumps blood to various parts of the body.
 Each half of the heart has a receiving chamber
called atrium, and a pumping chamber called
ventricle.
 2.Arteries- These are distributing channels, which
carry blood away from the heart.
 (a) They branch like trees on their way to different
parts of the body.
 The minute branches which are just visible to naked
eye are called arterioles.
3. Veins: These are draining channels which carry
blood from different parts of the body back to the
heart.
 The small veins (venules) join together to form
larger veins, which in turn unite to form great veins
called venae cavae

4. Capillaries
 These are networks of microscopic vessels
which connect arterioles with the venules.
 Types of capillary
 Capillaries have structural variations to
permit different levels of metabolic
exchange between blood and surrounding
tissues.
 They can be grouped into three types,
depending on
➯ structure of endothelial cells.
➯ absence / presence (continuity) of basal
laminae.


5. Continuous/somatic capillaries
Figure 19.3a
They are found in all types of muscle tissue, connective tissue, exocrine glands, and
nervous tissue

6. Fenestrated (visceral) capillaries
 Fenestrated (visceral) capillaries with diaphragms
I.Presence of large fenestrae (Ø = 60-80 nm) and are closed by a
diaphragm.
II.Have a continuous basal lamina.
III.Encountered in tissues where rapid interchange of substances
occurs between tissues and the blood
◦ ➯ kidney, pancreas, intestine, synovial membrane & endocrine
glands.

7. Fenestrated (visceral) capillaries
 Fenestrated (visceral) capillaries without diaphragms
I.No diaphragms present to close the openings.
II.Very thick basal lamina separates the endothelium from the
overlying epithelial cells (podocytes).
III.Characteristic of renal glomerulus.

8. Fenestrated Capillaries
Figure 19.3b

9. Sinusoidal (discontinuous) capillaries
 Sinusoidal (discontinuous) capillaries ➯ permeability barrier
is lacking.
I.have tortuous path and ↑↑ Ø (30-40 μm) ➯ slows blood circulation.
II.endothelial wall = discontinuous with multiple fenestrations
without diaphragms (basal lamina is discontinuous or is almost
completely absent).
III.pericytes only occur occasionally.
IV.macrophages are located among or outside the cells of the
endothelium.
V.found mainly in the liver, hypophysis, hemopoietic organs (bone
marrow, spleen…), lymph nodes and adrenal cortex.

10. Sinusoids
Figure 19.3c

12. Three-dimensional representation of the structure of a
capillary with fenestrae in its wall. The transverse section
shows that, in this example, the capillary wall is formed by
two endothelial cells. Note the basal lamina surrounding
endothelial cells.
Three-dimensional representation of the structure of a capillary with fenestrae in its wall. The transverse section
shows that, in this example, the capillary wall is formed by two endothelial cells. Note the basal lamina surrounding
endothelial cells.
criteria for classification
➯ structure of endothelial cells.
➯ absence / presence (continuity) of
basal laminae.

13.  These come in intimate contact with the tissues for a free exchange of
nutrients and metabolites across their walls between the blood and the
tissue fluid.
 Capillaries are replaced by sinusoids in certain organs, like liver and
spleen.

15. ANASTOMOSIS
 A precapillary or post capillary communication between the
neighbouring vessels is called anastomosis
 Circulation through the anastomosis is called collateral circulation.
Types-
 A. Arterial anastomoses,
 B. Venous anastomoses,
 C. Arteriovenous anastomosis (shunt)

16. A. Arterial anastomosis
 Is the communication between the arteries, or branches of arteries
 It may be actual or potential
 1. In actual arterial anastomosis - the arteries meet end to end. For example, palmar arches,
plantar arch, circle of Willis, intestinal arcades, labial branches of facial arteries.
 2. In potential arterial anastomosis - the communication takes place between the
terminal arterioles.
 This is called 'Potential' as it may develop slowly and be established when circulation
fails through one of the arteries.
 The examples are seen in the coronary arteries and the cortical branches of cerebral
arteries, etc.

17.  B. Venous anastomosis is the communication between the
veins or tributaries of veins.
 For example, the dorsal venous arches of the hand and foot

18.  C. Arteriovenous anastomosis (shunt) is the communication between an artery
and a vein

19. Porto-systemic anastomosis
 Porto-systemic anastomosis also known as portocaval anastomosis is
the collateral communication between the portal and the systemic venous
system.
 The portal venous system transmits deoxygenated blood from most of the
gastrointestinal tract and gastrointestinal organs to the liver via Portal
vein.
 When there is a blockage of the portal system, portocaval anastomosis
enable the blood to still reach the systemic venous circulation.
 Even though this is useful, bypassing the liver may be dangerous, since it
is the main organ in charge for detoxication and breaking down of
substances found in the gastrointestinal tract, such as mediactions but the
poisons as well.

20. Porto-systemic anastomosis
 The various anastomoses and the sites in which they occur are described below:
1. The anastomosis between the left gastric veins, which are portal veins, and the lower branches of
oesophageal veins that drain into the azygos and hemiazygos veins, which are systemic veins.
 The site of this anastomosis is the lower oesophagus.
2. The anastomosis between the superior rectal veins, which are portal veins, and the inferior and
middle rectal veins, which are systemic veins.
 The site of this anastomosis is the upper part of the anal canal.
3. The anastomosis between the paraumbilical veins, which run in the ligamentum teres as portal veins,
and small epigastric veins, which are systemic veins.
 The site of this anastomosis is the umbilicus.
4. The anastomosis between omental and colonic veins (portal veins) with the retroperitoneal veins
(systemic veins) in the region of hepatic and splenic flexure.

21. Clinical anatomy
 Portal hypertension
 This is increase in blood pressure in
the veins of the portal system.
 It is caused by blockage in the veins
of the liver due to pathological
conditions such as liver cirrhosis and
the inability of the blood to flow
through.
 Signs and symptoms are varicose
veins on the abdominal wall called
caput medusae, oesophageal varices,
enlargement of the spleen,
accumulation of fluid in the peritoneal
cavity and bleeding in the
gastrointestinal tract.

22. Types of Circulation of Blood
 Systemic (greater) circulation: The blood flows from the left ventricle,
through various parts of the body to the right atrium, i.e. from the left to the right
side of the heart

23.  Pulmonary (lesser) circulation: The blood flows from the right ventricle,
through the lungs, to the left atrium, i.e. from the right to the left side of the heart.

24. Portal Circulation/Systems
 Portal circulation: It is a part of systemic
circulation, which has the following characteristics
 The blood passes through two sets of capillaries
before draining into a systemic vein
 As a rule, capillary networks are interspersed
between terminal ramifications of arterial and
venous systems.
 This arrangement is modified to meet special
functional requirements.
 Blood from one capillary bed flows into a larger
vessel, having the histological characteristics of a
vein and this vessel later ramifies into capillaries
so that the blood flows through a second capillary
network before returning to the heart.

25. Portal Circulation/Systems
 Examples: hepatic portal circulation, hypothalamo hypophyseal portal
circulation ,and renal portal circulation.
Arterial portal system:
kidney glomerulus
Venous portal system:
Hepatic Portal System, Hypophyseoportal System

26. ARTERIES
 1. Arteries are thick-walled, being uniformly thicker than the
accompanying veins, except for the arteries within the cranium and
vertebral canal where these are thin.
 2.Arteries have no valves

27. Classification of arteries based on
their diameter
- Large or elastic arteries;
- Medium (or muscular or distributive) arteries; and
- Small arteries or arterioles, which are less than 0.5 mm in
diameter.

28. A characteristic feature of arteries
• Is a well-defined lumen, rounded or oval, maintained by the muscularity of the
vessel wall.
• The largest arteries, such as the aorta and its larger branches, have a tunica
media dominated by elastic tissue.
• Most arteries are muscular arteries, with a media dominated by smooth muscle.
But elastin is also a substantial component.

29. Types of Arteries and Structure
 Large arteries of elastic type, e.g. aorta and its main branches
(brachiocephalic, common carotid, subclavian and common iliac) and the
pulmonary arteries.
 Medium and small arteries of muscular type, e.g. temporal, occipital, radial,
popliteal, etc.
 Smallest arteries of muscular type are called arterioles.
 The side branches from terminal arterioles are called met arterioles

30. END-ARTERIES
 Arteries which do not anastomose with their neighbours are called end arteries
 Examples:
 1. Central artery of retina and labyrinthine artery of internal ear are the best examples
of an absolute end arteries.
 2. Arteries of spleen, kidney, lungs and metaphysis of long bones.
 Importance-Occlusion of an end-artery causes serious nutritional disturbances
resulting in death of the tissue supplied by it. For example, occlusion of central artery
of retina results in blindness.

31. Blood Supply of Arteries
 The large arteries (of more than 1 mm diameter) are supplied with blood vessels.
 The nutrient vessels, called vasa vasorum, form a dense capillary network in the tunica
adventitia, and supply the adventitia and the outer part of tunica media.
 Minute veins accompanying the arteries drain the blood from the outer part of arterial wall.

32. Nerve Supply of Arteries
 The nerves supplying an artery are called nervi vascularis.
 The nerves are mostly non-myelinated sympathetic fibres which are vasoconstrictor in
function.
Vasodilator innervation is restricted to the following sites.
 The skeletal muscle vessels are dilated by cholinergic sympathetic nerves.
 The exocrine gland vessels are dilated on parasympathetic stimulation.

33. VEINS
 1. Veins are thin-walled, being thinner than the arteries
 2. Their lumen is larger than that of the accompanying arteries
 3. Veins have valves which maintain the unidirectional flow of blood, even against gravity
 4. The muscular and elastic tissue content of the venous walls is much less than that of
the arteries

34.  Large veins have dead space around them for their
dilatation during increased venous return

36. Blood and Nerve Supply of Veins
 The larger veins, like the arteries, are supplied with nutrient vessels called vasa
vasorum
 Nerves also are distributed to the veins in the same manner as to the arteries, but are
fewer in number.

37. Factors Helping in Venous Return
 Negative intrathoracic pressure sucks the blood into the heart from all over the body.
 Gravity helps venous return in the upper part of the body.
 Arterial pulsations press on the venae comitantes intermittently and drive the venous
blood towards the heart.

38.  Muscular contractions press on the veins and form a very effective mechanism of
venous return
The calf muscles (soleus) for this reason are known as the peripheral heart.
Thus the muscle pumps are important factors in the venous return.

39. Clinical Anatomy
 The blood pressure is the arterial pressure exerted by the
blood on the arterial walls.
 The maximum pressure during ventricular systole is called systolic
pressure; the minimum pressure during ventricular diastole is called
diastolic pressure.
 Normally, the blood pressure is roughly 120/80 mm Hg, the systolic
pressure ranging from 110-130, and the diastolic pressure from 70-80.

40. Clinical Anatomy
 Atheroma:- are patchy changes developed in the tunica intima of
arteries due to accumulation of cholesterol and other lipid compounds
 Aneurysm:- is the swelling or dilation of blood vessels where part
of the wall of artery inflates like a balloon. Due to its likelihood to burst, it
poses a serious risk to health
 Varicose veins:- When the vein wall is subjected to increased pressure
over long time, there is atrophy of muscle and elastic tissue with fibrous
replacement. This leads to stretching of the vein with tortuosity and
localized bulging.

41. Clinical Anatomy

43. The Mediastinum

44. The Mediastinum
 Area between the two lungs and
pleural cavities
 Divided by transverse thoracic
plane (passing through sternal
angle & T4/5) into:
◦ Superior mediastinum:
◦ Inferior mediastinum is
subdivided in to 3 parts by
the pericardium.
 Anterior mediastinum
 Middle mediastinum
 Posterior mediastinum

45. Anterior mediastinum
 Narrow space in front of the pericardium and behind the body of
sternum
 Contents
◦ Thymus (lower part)
◦ Sternopericardial ligaments
◦ Parasternal lymph nodes
◦ Transverse thoracis muscle

46. Middle mediastinum
 The pericardium and its contents (heart and roots of its great vessels)
 Boundary
◦ superior - imaginary line
◦ Inferior- diaphragm (where the pericardium rests)
◦ Right and left lateral – corresponding Mediastinal surfaces of pleura
◦ Anterior – anterior mediastinum and part of pleura
◦ Posterior – posterior mediastinum
 Contents
◦ The heart and the pericardium
◦ Great vessels – SVC, IVC, Pulmonary trunk & veins, part of aorta,
parts of the phrenic nerve

47. Pericardium
 Fibroserous sac that encloses the heart and the roots of the great
vessels.
 It has 2 layers
◦ Fibrous pericardium
◦ Serous pericardium
 Fibrous Pericardium
◦ Tough connective tissue outer layer of the sac.
◦ It fuses with the roots of the great vessels.
◦ Attached in front to the sternum by the sternopericardial ligaments
and to the central tendon of the diaphragm below.
◦ Protects the heart; anchors the heart; and prevents sudden
overfilling.

48. Pericardium

49. Pericardium
 Serous Pericardium
◦ Has two parts
 Parietal layer – lines inner surface the fibrous pericardium
 Visceral layer (epicardium) – adheres to the heart & forms outer layer
of the heart wall
◦ Pericardial cavity – narrow space between the two layers of serous
pericardium
 contains a small amount of fluid, Pericardial fluid
 create a relatively friction-free environment for movement of the heart
◦ The parietal and visceral layers of serous pericardium are continuous at
the roots of the great vessels.

50. Pericardial Sinuses
 Pericardial reflection from the parietal to
visceral
 Oblique sinus – forms a recess between the
left atrium and the pericardium on the
posterior part of the heart
◦ bounded by IVC and four pulmonary veins
 Transverse sinus
◦ short passage that lies between the
reflection of serous pericardium around the
aorta and pulmonary trunk and SVC.
◦ Used for ligating large vessels during cardiac
surgery.

51. Pericardial Sinuses

52. Pericardium: Blood supply and innervation
 Fibrous and Parietal pericardium
◦ Arteries – pericardiacophrenic artery from the internal thoracic a. (main).
 Musculophrenic, bronchial, esophageal, and superior phrenic arteries
◦ Veins – to pericardiacophrenic & azygos vein
◦ Nerve – Phrenic nerves (C3-C5)- primary source of sensory fibers - pain
sensations conveyed by these nerves are commonly referred to the skin
(C3-C5 dermatomes) of the ipsilateral supraclavicular region.
 Visceral pericardium
◦ Artery – coronary arteries
◦ Vein – coronary sinus
◦ Nerve – autonomic nerves of heart; not sensitive to pain

53. Medical Application
 Pericarditis - inflammation of the pericardium
 Is an Inflammation of the pericardium
 Usually causes chest pain
 It may also make the serous pericardium rough
 If there is pericarditis, friction of the roughened surfaces may sound like
the rustle of silk when listening with a stethoscope over the left sternal
border and upper ribs
◦ pericardial friction rub
 Pericardial effusion – collection of excess fluid in pericardial cavity

54. Medical Application
Cardiac tamponade
• It is heart compression because
pericardial cavity is occupied by other
than normal occupant.
• If extensive pericardial effusion exists, the
sac does not allow full expansion of the
heart, limiting the amount of blood the
heart can receive, which in turn reduces
cardiac output.
• Cardiac tamponade is a potentially lethal
condition because heart volume is
increasingly compromised.
 Pericardiocentesis - Drainage of
fluid from the pericardial cavity.
◦ puncture is at left 5th/6th
intercostal space or between
xiphoid process and left side of
infrasternal angle, needle inserted
superoposteriorly.

55. Layers of the Heart Wall
 Composed of 3 layers (superficial to
deep)
◦ Epicardium – outer layer
 is the visceral layer of serous
pericardium.
◦ Myocardium – middle muscular
and thickest layer
 Layer of cardiac muscle
◦ Endocardium – inner layer
 Is endothelium (squamous
epithelium)
 lines the heart chambers and
covers the valves

56. The Heart
 slightly larger than loosely
clenched fist.
 It weighs between 250 - 350
grams.
 Lies from the 2nd rib to 5th
intercostal space
 Situated in the middle
mediastinum.
 Placed obliquely
◦ 2/3rd of the heart lies to the left
of the midsternal line

57. The Heart

58. The Heart- surface anatomy
The heart is said to have four corners defined by four points
projected onto the anterior thoracic wall,
1. The superior right point lies where the costal cartilage of
the third rib joins the sternum.
2. The superior left point lies at the costal cartilage of the
second rib, a finger’s breadth lateral to the sternum.
3. The inferior right point lies at the costal cartilage of the
sixth rib, a finger’s breadth lateral to the sternum.
4. Finally, the inferior left point (the apex point) lies in the
fifth intercostal space at the midclavicular line—that is, at a line
extending inferiorly from the midpoint of the left clavicle.
The imaginary lines that connect these four corner points
delineate the normal size and location of the heart.
- Clinically important specially in x-ray.

59. The Heart
Heart- Muscular double
pump(Right and Left
pump).

60. The Heart
 The heart and roots of the great vessels within the pericardial sac are
related anteriorly to the sternum, costal cartilages, and anterior ends of
the 3rd - 5th ribs on the left side
 The heart has four chambers: right atrium, left atrium, right ventricle
and left ventricle.
 The atria are receiving chambers that pump blood into the ventricles
(the discharging chambers)
 The right side of the heart receives poorly oxygenated blood from the
body through the venae cavae and coronary sinus, and pumps it
through the pulmonary trunk to the lungs for oxygenation.
62

61. The Heart
 The left side of the heart receives
well oxygenated blood from the
lungs through the pulmonary veins
and pumps it into the aorta for
distribution to the body.
 The synchronous pumping actions
of the heart's two atrioventricular
(AV) pumps (right and left
chambers) constitute the cardiac
cycle
63

62. Cardiac cycle
 The cycle begins with a period of ventricular elongation and filling
(diastole) and ends with a period of ventricular shortening and
emptying (systole).
 Two heart sounds are heard with a stethoscope:
1st a lub sound as the blood is transferred from the atria into the
ventricles, and
2nd a dub sound as the ventricles expel blood from the heart.
 The heart sounds are produced by the snapping shut of the one way
valves that normally keep blood from flowing backward during
contractions of the heart.
64

63. The wall of the Heart
The wall of each heart chamber consists of
three layers:
 Endocardium- a thin internal layer or
lining membrane of the heart that also
covers its valves
 Myocardium- a thick helical middle
layer composed of cardiac muscle
 Epicardium - a thin external layer
formed by the visceral layer of serous
pericardium
 The walls of the heart consist mostly of
thick myocardium, especially in the
ventricles.
 The cardiac muscle fibers are anchored to
the fibrous skeleton of the heart.
65

64. The fibrous skeleton of
the heart
 This is a complex framework
of dense collagen forming
four fibrous rings that
surround the orifices of the
valves.
66

65. Function of The fibrous skeleton of the heart
I. Keeps the orifices of the AV and semilunar valves patent.
II. Prevents the valves from being overly distended by an increased
volume of blood pumping through them.
III. Provides attachments for the leaflets and cusps of the valves.
IV. Provides attachment for the myocardium, which when uncoiled,
forms a continuous ventricular myocardial band.
V. Forms an electrical “insulator,” by separating the myenterically
conducted impulses of the atria and ventricles.
67

66. Heart Chambers
 The heart has four chambers
◦ Two atria
◦ Two ventricles
 The atria lie above and behind ventricles
 Upper part of each atrium has an appendage called auricle
 The chambers are internally separated by the septum
◦ Interatrial septum - Between atria
◦ Interventricular septum - Between ventricles
◦ Atrioventricular septum – between atria and ventricles

67. Heart Chambers: grooves
 Grooves/Sulcus
◦ indicate the boundaries of
its four chambers
externally
◦ carry coronary vessels
 Atrioventricular groove or
coronary sulcus –separate the
atria from the ventricles
 Interventricular groove –
separate the 2 ventricles from
each other
◦ Anterior and posterior

68. The Heart
 Shape: pyramidal with apex, base
and 4 borders and 4 surfaces
 The apex
◦ Directed downwards, forwards
and to the left
◦ Lies in left 5th intercostal space
about 9cm away from midline,
just medial to midclavicular line
◦ Formed by inferolateral part of
left ventricle

69. The Heart
 The base
◦ Forms the posterior surface
◦ directs to right shoulder.
◦ At vertebral levels of T6–T9.
◦ Between bifurcation of
pulmonary trunk and coronary
groove.
◦ Formed mainly by left atrium
(2/3) and small part of right
atrium (1/3).

70. The Heart
 Borders
◦ Right – formed by right atrium;
in line with SVC and IVC.
◦ Left – formed mainly by left
ventricle and partly by left auricle.
◦ Inferior – formed mainly by right
ventricle; left ventricle near the
apex.
◦ Superior – slightly oblique, formed
by two atria.

71. 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.
 Dextrocardia is associated with mirror
image positioning of the great vessels
and the arch of the aorta.
73

72. 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 isolated dextrocardia, however, the
congenital anomaly is complicated by
severe cardiac anomalies, such as
transposition of the great arteries.
74

73. The Heart
 Surfaces
◦ Anterior (sternocostal) surface – formed mainly by right
ventricle
◦ Diaphragmatic (inferior) surface
 formed by left ventricle (left 2/3) and right ventricle (right 1/3)
 Rests on central tendon of diaphragm
◦ Left pulmonary surface – formed by left ventricle
◦ Right pulmonary surface – formed by right atrium

74. The heart - Surfaces
 The anterior or sternocostal surface
is formed mainly by the right atrium
and right ventricle: and partly by the
left ventricle and left auricle.
 Most of the sternocostal surface is
covered by the lungs, but a part of it
that lies behind the cardiac notch of
the left lung is uncovered.
 The uncovered area is dull on
percussion.
 Clinically it is referred to as the area
of superficial cardiac dullness.

75. Right Atrium
 Forms the right border, the sternocostal surface and base of the heart
 Receives venous blood from the body through
◦ SVC (at the level of 3rd costal cartilage)
◦ IVC (at the level of 5th costal cartilage)
◦ Coronary sinus – drains most of the venous blood from the
heart wall
 Right Auricle
◦ Ear-like muscular pouch on the upper anterior portion of the
right atrium
◦ increase the atrial capacity slightly

76. Right Atrium: Internal
features
 The interior has 3 parts
◦ smooth posterior part
(sinus venarum)
 SVC & IVC opens into it
 Coronary sinus opens
between IVC orifice and
right AV orifice
◦ Rough anterior part
(pectinate part)
 Contains muscular ridges,
pectinate muscles
◦ Right AV orifice

77. Right Atrium: Internal
features
The Smooth Posterior Part or Sinus
Venarum
 1. Developmentally it is derived from
the right horn of the sinus venosus
 2. Most of the tributaries open to
this part,except the anterior cardiac
veins which open into anterior part
 1)The superior vena cava opens at
the upper end.
 (2) the inferior vena cava opens at
the lower end,opening is guarded by
rudimentary valve of inferior
venacava or eustachian valve.

78. Right Atrium: Internal
features
 Sulcus terminalis - a shallow
groove externally along right border
that runs from SVC to IVC vertically
◦ Separate the rough and smooth
parts externally
◦ internally indicated by the crista
terminalis (smooth, muscular
ridge)
◦ upper end is landmark of SA node

79. Right Atrium: Internal
features
 It presents a series of transverse
muscular ridges called musculi
pectinati.
 They arise from the crista
terminalis and run forwards and
downwards towards the
atrioventricular orifice, giving the
appearance of the teeth of a comb.

80. Right Atrium: Internal
features
 Interatrial septum
◦ Separate the atria
◦ Has a shallow depression, fossa
ovalis
 Remnant of the foramen ovale
◦ Limbus fossa ovalis: upper
margin of fossa ovalis.

81. Right Ventricle
 Forms
◦ Most of the anterior surface
of the heart
◦ a small part of diaphragmatic
surface
◦ Entire inferior border
 Receive blood from right atrium
and pump into pulmonary
trunk.

82. Right Ventricle
 Internal structure consist of two
parts
◦ Smooth outflow part – conus
arteriosus/ infundibulum
(pulmonary trunk arise)
◦ Rough inflow part – due to
muscular ridges called
trabeculae carneae.

83. Right Ventricle
 Papillary muscles
◦ Conical projections arise from ventricular wall whose free ends are for
chordae tendineae.
◦ The papillary muscles begin to contract before contraction of the right
ventricle, tightening the tendinous cords and drawing the cusps
together.
◦ Three: - Anterior
- Posterior &
- Septal

84. Right Ventricle
 Because the cords are attached to adjacent sides of two cusps, they
prevent separation of the cusps and their inversion when tension is
applied to the tendinous cords and maintained throughout ventricular
contraction
Thus regurgitation of blood (backward flow of blood) from the right
ventricle back into the right atrium is blocked by the valve cusps

85. Right Ventricle
The anterior papillary muscle:
 The largest and most prominent
of the three.
 Arises from the anterior wall of
the right ventricle.
 Its tendinous cords attach to the
anterior and posterior cusps of
the tricuspid valve.
87

86. Right Ventricle
The posterior papillary muscle:
 Smaller than the anterior muscle
 May consist of several parts
 It arises from the inferior wall of the right ventricle
 Its tendinous cords attach to the posterior and septal cusps of the
tricuspid valve.
The septal papillary muscle:
 Arises from the interventricular septum
 Its tendinous cords attach to the anterior and septal cusps of the
tricuspid valve.
88

87. 89

88. Right Ventricle
 Interventricular septum
◦ Partition between ventricles
◦ Composed of membranous and muscular parts
 Membranous part – superoposterior, thin, continuous with fibrous
skeleton
 Muscular part – thick, bulges to the right
- Because of the much higher blood pressure in the left ventricle, the
muscular part the IVS is two to three times as thick as the wall of the
right ventricle.

89. Right Ventricle
 Superiorly and posteriorly, a thin
membrane, part of the fibrous
skeleton of the heart, forms the
much smaller membranous part of
the interventricular septum.
 On the right side, the septal cusp of
the tricuspid valve is attached to
the middle of this membranous part
of the fibrous skeleton.
91

90. Right Ventricle
 Inferior to the septal cusp, the
membranous part of the fibrous
skeleton forms interventricular
septum.
 Superior to the septal cusp, the
membranous part of the fibrous
skeleton forms an
atrioventricular septum,
separating the right atrium from
the left ventricle.
92

91. Right Ventricle
Septomarginal trabecula
(moderator band)
◦ Muscular bundle runs from
interventricular septum to base of
anterior papillary muscle.
◦ Carries part of the right bundle of
the AV bundle of conducting
system.
◦ Facilitate conduction time
allowing contraction of the
papillary muscle before
contraction of ventricle wall.

92. Right Ventricle
 The right atrium contracts when the right ventricle is empty and
relaxed; thus blood is forced through right AV orifice into the right
ventricle, pushing the cusps of the tricuspid valve aside like curtains.
 The inflow of blood into the right ventricle enters posteriorly; and when
the ventricle contracts, the outflow of blood into the pulmonary trunk
leaves superiorly and to the left.
94

93. Right Ventricle
 Consequently, the blood takes a U-shaped
path through the right ventricle.
 This change in direction is accommodated by
the supraventricular crest, which deflects the
incoming flow into the main cavity of the
ventricle, and the outgoing flow into the
conus arteriosus toward the pulmonary
orifice.
 The inflow (AV) orifice and outflow
(pulmonary) orifice are approximately 2 cm
apart.
 The pulmonary valve at the apex of the conus
arteriosus is at the level of the left 3rd costal
cartilage. 95

94. Atrial Septal Defects(ASD)
 Is a congenital anomaly of the
interatrial septum, usually
incomplete closure of the Foramen
ovale.
 Clinically significant ASDs vary
widely in size and location and may
occur as part of more complex
congenital heart disease.
 It allows blood to be shunted from
the left atrium through the ASD
into the right atrium
96

95. Atrial Septal Defects
 This left to right shunt of blood
overloads the pulmonary
vascular system, resulting in
hypertrophy of the right atrium
and ventricle and pulmonary
arteries.
97

96. Ventricular Septal Defects(VSD)
 The membranous part of the IVS
develops separately from the muscular
part.
 Consequently, this part is the common
site of ventricular septal defects,
although defects also occur in the
muscular part
 The much less common VSD in the
muscular part of the septum frequently
closes spontaneously during childhood
98

97. Ventricular Septal Defects
 A VSD causes a left to right shunt of
blood through the defect.
 A large shunt increases pulmonary
blood flow, which causes severe
pulmonary disease(hypertension) and
may cause cardiac failure
99

98.  (A) Atrial septal defect
 (B) ventricular septal
defect
100

99. Left Atrium
 Forms most of the base of the
heart.
 Blood enters via four valveless
veins
◦ 2 Right and 2 left pulmonary
veins - open through the
posterior wall.
 Thicker than right atrium
 Interior is smooth
◦ left auricle possesses muscular
ridges.

100. Left Atrium
 In the embryo, there is only one
common pulmonary vein, just as there is
a single pulmonary trunk.
 The tubular, muscular left auricle, its
wall trabeculated with pectinate
muscles, forms the superior part of the
left border of the heart and overlaps the
root of the pulmonary trunk.
 A semilunar depression in the interatrial
septum indicates the floor of the oval
fossa ; the surrounding ridge is the valve
of the oval fossa.

101. Left Atrium
 Musculi pectinati are present only
in the auricle where they form a
reticulum.
 The septal wall shows the fossa
lunata corresponding to the fossa
ovalis of the right atrium

102. Left Ventricle
 Forms the apex of the heart, most of
diaphragmatic surface and left border.
 Receive blood from left atrium & pumps
into the aorta.
 3 times thicker than that of the right
ventricle
 The cavity is circular and longer than
the right.

103. Left Ventricle
 Internal structure
 The interior is divisible into two parts:
 (i) the lower rough part with trabeculae
carneae ,develops from the primitive ventricle
of the heart tube,
 (ii) the upper smooth part or aortic vestibule
gives origin to the ascending aorta
 Trabeculae carneae are finer and more
numerous than the right.
 Papillary muscles: two; anterior and
posterior
 Smooth walled posterosuperior part – aortic
vestibule, leads to aortic orifice.

104. Left Ventricle
 Anterior and posterior papillary muscles that are larger than those in the
right ventricle
 A smooth-walled, non-muscular, superoanterior, outflow part, the aortic
vestibule, leading to the aortic orifice and aortic valve.
 A double-leaflet mitral valve that guards the left AV orifice.
 An aortic orifice that lies in its right posterosuperior part and is surrounded
by a fibrous ring to which the Right, Posterior, and Left cusps of the aortic
valve are attached; the ascending aorta begins at the aortic orifice.
106

105. Left Ventricle
 The mitral valve is located posterior to the sternum at the level of the 4th
costal cartilage
 The mitral valve has two cusps, anterior and posterior, each of its cusps
receives tendinous cords from more than one papillary muscle
 These muscles and their cords support the mitral valve, allowing the cusps to
resist the pressure developed during contractions of left ventricle.
 The tendinous cords become taut just before and during systole, preventing
the cusps from being forced into the left atrium
 As the bloodstream traverses the left ventricle, it undergoes two right angle
turns
 This reversal of flow takes place around the anterior cusp of the mitral valve
107

106. Left Ventricle

107. Heart Valves
 Prevent backflow of blood (ensure one way flow of blood)
 Heart valves are positioned between the atria and the ventricles and
between the ventricles and the large arteries that leave the heart
 Valves open and close in response to differences in blood pressure

108. Heart: internal features

109. Atrioventricular (AV) Valves
 Located at each atrioventricular junction
◦ Right AV valve (tricuspid) – has three flexible cusps
 anterior, posterior & septal
◦ Left AV valve (bicuspid/mitral) – has two flexible cusps
 anterior and posterior
 The cusps are flaps of endocardium reinforced by connective tissue
 The chordae tendinae anchor the cusps to the papillary muscles
◦ Prevents separation and inversion of the cusps during systole

110. Atrioventricular (AV) Valves
 Left atrioventricular valve is known as bicuspid valve because it has two
cusp (mitral valve),resembling bishops Mitre

111. Atrioventricular (AV) Valves

112. Semilunar (SL) Valves
 They are smaller in area than the cusps of the AV valves
 The force exerted on them is less than half that exerted on the cusps of
the tricuspid and mitral valves
 Semilunar cusps do not have tendinous cords to support them
 The cusps project into the artery but are pressed toward (and not
against) its walls as blood leaves the ventricle
 After relaxation of the ventricle (diastole), the elastic recoil of the wall
of the pulmonary trunk or aorta forces the blood back toward the heart,
leading the cusps to close as they catch the reversed blood flow
114

113. Semilunar (SL) Valves

114. Semilunar (SL) Valves
 The cusps come together to completely close the orifice, supporting each
other as their edges abut (meet), and preventing any significant amount
of blood from returning to the ventricle.
 Immediately superior to each semilunar cusp, the walls of the origins of
the pulmonary trunk and aorta are slightly dilated, forming a sinus.
 The blood in the sinuses and the dilation of the wall prevent the cusps
from sticking to the wall of the vessel, which might prevent closure
 The mouth of the right coronary artery is in the right aortic sinus, the
mouth of the left coronary artery is in the left aortic sinus, and no artery
arises from the posterior aortic (non-coronary) sinus
116

115. 117

116. Aortic Semilunar valve
 The aortic semilunar valve, between
the left ventricle and the ascending
aorta, is obliquely placed
 This valve has three cusps(posterior,
left and right)
 It is located posterior to the left side
of the sternum at the level of the 3rd
intercostal space
118
 Aortic semilunar valve

117. Pulmonary Semilunar Valves
 This valve has three
cusps(anterior, right, and left)
 Is located between right ventricle
and Pulmonary trunk posterior to
left 3rd costal cartilage.
119
 Pulmonary semilunar valve

118. Valvular Heart Disease
 Disorders involving the valves of the heart disturb the pumping
efficiency of the heart.
 Valvular heart disease produces either stenosis (narrowing) or
insufficiency
 Stenosis is the failure of a valve to open fully, slowing blood flow from a
chamber
 Insufficiency is failure of the valve to close completely, This allows a
variable amount of blood to flow back into the chamber it was just
ejected from.
120

119. Valvular Heart Disease
 Both stenosis and insufficiency result in an increased workload for the
heart.
 Restriction of high-pressure blood flow or passage of blood through a
narrow opening into a larger vessel or chamber produces turbulence.
 Turbulence sets up eddies(small whirlpools) that produce vibrations that
are audible as murmurs, Superficial vibratory sensations (thrills) may be
felt on the skin over an area of turbulence.
121

120. Valvular Heart Disease- TAVR/open heart surgery

121. Contraction and relaxation of the heart
 Cardiac cycle
◦ synchronous pumping action of the heart two pumps
◦ Diastole – ventricular elongation (relaxing) and filling with
blood
◦ Systole – period of ventricular shortening (contraction) and
emptying
 The two atria contract together, followed by the simultaneous contraction of
the two ventricles
 Systole and diastole refers to the ventricles which are the dominant heart
chambers

122. Heart Sounds
 The closing of the heart valves causes heart sounds
◦ S1 - “lub”
 first heart sound
 produced by the closing of the AV valves
 occurs at the start ventricular systole
◦ S2 - “dup”
 second heart sound
 produced by the closing of the semilunar valves
 occurs during ventricular diastole/ at the end of ventricular systole
 Sounds are heard away from the valves in the direction of the blood flow

123. Surface markings of the valves and auscultation areas
Valve
(diameter)
Surface marking Auscultation area
Pulmonary (2.5
cm)
Upper border of 3rd left costal cartilage
near sternum
Sternal end of 2nd left
intercostal space
Aortic
(2.5 cm)
Behind left half of sternum at the level
of medial end of 3rd intercostal space
Sternal end of 2nd right
intercostal space
Mitral
(3 cm)
Behind the left half of sternum
opposite to 4th costal cartilage
5th left intercostal space
(cardiac apex) at midclavicular
line
Tricuspid
(4 cm)
Behind the right half of sternum
opposite to 4th and 5th intercostal
space
5th left intercostal space near
sternal body

124. Surface markings of the valves and auscultation areas

125. Conducting System of the heart
 series of specialized cardiac muscle cells that
carries impulses throughout the heart
musculature
 signal them to contract rhythmically
 Components of the conducting system:
◦ Sinoatrial (SA) node
◦ Internodal fibers
◦ Atrioventricular (AV) node
◦ Atrioventricular bundle
◦ Right and left bundle branches
◦ Purkinje fibers

126. Conducting System of the heart

127. SA (Sinoatrial) node
 Located anterolaterally in the wall of the right atrium
◦ below the entrance of the SVC near superior end of crista
terminalis
 Initiates and regulates the impulses for contraction
 pacemaker of the heart
 generates 70-80 impulses per minute
 Impulses from the SA node spread in a wave along the cardiac muscle
fibers of the atria signaling the atria to contract

128. SA (Sinoatrial) node
 The contraction signal from the SA
node spreads myogenically
through the musculature of both
atria.
 The SA node is stimulated by the
sympathetic division of the
autonomic nervous system to
accelerate the heart rate and is
inhibited by the parasympathetic
division to return to (approach) its
basal rate.
130

129. The atrioventricular (AV) node
 Is a smaller collection of nodal
tissue than the SA node.
 Located in the posteroinferior
region of the interatrial septum
near the opening of the coronary
sinus.
 The signal generated by the SA
node passes through the walls of
the right atrium, and transmitted
rapidly to the AV node.
131

130. The atrioventricular (AV) node
 The AV node then distributes the signal to the ventricles through the AV
bundle
 Sympathetic stimulation speeds up conduction, and parasympathetic
stimulation slows it down
132

131. The AV bundle (bundle of hiss)
 Is the only bridge between the atrial and ventricular myocardium, passes
from the AV node through the insulating fibrous skeleton and along the
membranous part of the IVS.
 At the junction of the membranous and muscular parts of the septum, the
AV bundle divides into right and left bundles.
 These branches proceed on each side of the muscular IVS deep to the
endocardium and then ramify into subendocardial branches (Purkinje
fibers), which extend into the walls of the respective ventricles
 The subendocardial branches of the right bundle stimulate the muscle of
the IVS, the anterior papillary muscle through the septomarginal trabecula,
and the wall of the right ventricle
133

132. 134

133. Innervation of the Heart
 The heart is supplied by autonomic nerve fibers from the cardiac plexus
 This plexus lies on the anterior surface of the bifurcation of the trachea,
and posterior surface of aorta and pulmonary trunk
 Fibers extend from the plexus along and to the coronary vessels and to
components of the conducting system, particularly the SA node.
 The cardiac plexus is formed of both sympathetic and parasympathetic
fibers running to the heart
135

134. 136

135. Innervation of the Heart
 Sympathetic supply is from:
 Presynaptic fibers- with cell bodies in the cell columns of the superior
five or six thoracic segments of the spinal cord.
 Postsynaptic fibers- with cell bodies in the cervical and superior
thoracic paravertebral ganglia of the sympathetic trunks.
 Sympathetic stimulation:
 Increases heart rate
 Increases impulse conduction
 Increases force of contraction
 Increases blood flow through the coronary vessels to support the
increased activity
137

136. Innervation of the Heart

137. Innervation of the Heart
 The parasympathetic supply is from:
 Presynaptic fibers of the vagus nerves
 Postsynaptic parasympathetic cell bodies located in the atrial wall
and interatrial septum near the SA and AV nodes and along the
coronary arteries.
 Parasympathetic stimulation:
 slows the heart rate
 reduces the force of the contraction
 constricts the coronary arteries, saving energy between periods of
increased demand.
139

138. Arterial Supply of the Heart
 The coronary arteries, the first branches of the aorta, supply the
myocardium and epicardium.
 The right and left coronary arteries arise from the corresponding aortic
sinuses at the proximal part of the ascending aorta, just superior to the
aortic valve, and pass around opposite sides of the pulmonary trunk.
 The coronary arteries supply both the atria and the ventricles; however,
the atrial branches are usually small and not readily apparent in the
cadaveric heart
 The ventricular distribution of each coronary artery is not sharply
demarcated.
140

139. 141

140. The right coronary artery (RCA)
 Arises from the right aortic sinus of the ascending aorta and passes to the
right side of the pulmonary trunk, running in the coronary groove.
 Near its origin, the RCA usually gives off an ascending sinuatrial nodal
branch, which supplies the SA node.
 The RCA then descends in the coronary groove and gives off the right
marginal branch, which supplies the right border of the heart as it runs
toward the apex of the heart.
 After giving off this branch, the RCA continues in the coronary groove to
the posterior aspect of the heart.
142

141. The right coronary artery (RCA)
 At the crux of the heart, the RCA gives rise to the
atrioventricular nodal branch, which supplies
the AV node
 The RCA gives rise to the large posterior
interventricular branch, which descends in the
posterior IV groove toward the apex of the heart.
 The posterior inter ventricular branch supplies
adjacent areas of both ventricles and sends
perforating interventricular septal branches into
the interventricular septum
 The terminal (left ventricular) branch of the RCA
then continues for a short distance in the coronary
groove.
143

142. 144

143. The right coronary artery (RCA)
 Typically, the RCA supplies
 The right atrium
 Most of right ventricle
 Part of the left ventricle(diaphragmatic surface)
 Part of the IV septum(usually the posterior 1/3)
 The SA node (in approximately 60% of people)
 The AV node (in approximately 80% of people)
145

144. 146

145. The left coronary artery (LCA)
 Arises from the left aortic sinus of the ascending aorta, passes between
the left auricle and the left side of the pulmonary trunk, and runs in the
coronary groove.
 As it enters the coronary groove, at the superior end of the anterior
interventricular(IV) groove, the LCA divides into two branches, the
anterior IV branch and the circumflex branch.
 The anterior IV branch passes along the IV groove to the apex of the
heart.
 Here it turns around the inferior border of the heart and commonly
anastomoses with the posterior IV branch of the right coronary artery
 The anterior IV branch supplies adjacent parts of both ventricles and, via
IV septal branches, the anterior 2/3 of the IVS
147

146. The left coronary artery (LCA)

147. The left coronary artery (LCA)
 In many people, the anterior IV branch gives rise to a lateral (diagonal)
branch, which descends on the anterior surface of the heart
 The smaller circumflex branch of the LCA follows the coronary groove
around the left border of the heart to the posterior surface of the heart.
 In approximately 40% of people, the SA nodal branch arises from the
circumflex branch of the LCA and ascends on the posterior surface of
the left atrium to the SA node
 The left marginal artery, a branch of the circumflex branch, follows
the left margin of the heart and supplies the left ventricle.
149

148. The left coronary artery (LCA)
 Typically, the LCA supplies:
The left atrium
Most of the left ventricle
Part of the right ventricle
Most of the IVS (usually its anterior 2/3), including AV bundle,
through its perforating IV septal branches
The SA node (in approx. 40% of people)
150

149. 151

150. Variations of the Coronary Arteries
 Variations in the branching patterns, distribution & dominance of the
coronary arteries are common
 Dominance of the coronary arterial system is defined by which artery gives
rise to the posterior interventricular artery(Posterior descending artery)
 In the most common right dominant pattern, present in approximately 67%
of people.
 In approx. 15%, the LCA is dominant
 There is codominance in approx. 18%
 A few people have only a single coronary artery
 In other people, the circumflex branch arises from the right aortic sinus
 Approx. 4% have an accessory coronary artery
152

151. Coronary Collateral Circulation
 The branches of the coronary arteries are generally considered to be
end arteries.
 However, anastomoses exist between branches of the coronary,
subepicardial or myocardial, and between these arteries and
extracardiac vessels such as thoracic vessels
 Anastomoses exist between the terminations of the right and the left
coronary arteries in the coronary groove and between the IV branches
around the apex in approx. 10% of normal hearts.
153

152. Venous Drainage of the
Heart
 The heart is drained mainly by
veins that empty into the
coronary sinus and partly by
small veins that empty into the
right atrium.
154

153. The Coronary Sinus
 Coronary sinus is the main vein of the
heart.
 Is a wide venous channel that runs
from left to right in the posterior part
of the coronary groove.
 Receives the great cardiac vein at its
left end and the middle cardiac &
small cardiac veins at its right end.
 The left posterior ventricular vein and
left marginal vein also open into the
coronary sinus.
155

154. The great cardiac vein
 Is the main tributary of the coronary
sinus
 Its 1st part (anterior IV vein) begins
near the apex and ascends with the
anterior IV artery
 At the coronary groove it turns left,
and its 2nd part runs around the left
side of the heart with the circumflex
artery to reach the coronary sinus
 The great cardiac vein drains the
areas of the heart supplied by the
LCA.
156

155. The middle and small cardiac veins
 The middle cardiac vein
(posterior IV vein) accompanies
the posterior interventricular artery
 A small cardiac vein
accompanies the right marginal
artery
 Thus these two veins drain most
of the areas commonly supplied by
the RCA.
157

156. CLINICAL ANATOMY
Stroke or Cerebrovascular Accident
 Thrombi (clots) form on the walls of the
left atrium in certain types of heart
disease.
 If these thrombi detach, or pieces break
off from them, they pass into the systemic
circulation and occlude peripheral arteries.
 Occlusion of an artery supplying the brain
results in a stroke or cerebrovascular
accident (CVA), which may affect vision,
cognition, or the motor function of parts
of the body previously controlled by the
now-damaged (ischemic) area of the
brain.

157. CLINICAL ANATOMY
Coronary Artery Disease
 Coronary angiography is a
procedure that uses contrast dye,
usually containing iodine, and x ray
pictures are done to detect
blockages in the coronary arteries
that are caused by plaque buildup.
 determines the sites of narrowing
or occlusion of the coronary
arteries or their branches.

158. CLINICAL ANATOMY
 Using coronary angiography, the coronary arteries can be visualized with coronary arteriograms .
 A long, narrow catheter is passed into the ascending aorta via the femoral artery in the inguinal region.
 Under fluoroscopic control, the tip of the catheter is placed just inside the opening of a coronary artery
 A small injection of radiopaque contrast material is made, and cineradiographs (short movie film recordings)are
taken to show the lumen of the artery and its branches, as well as any stenotic areas that may be present.

159. CLINICAL ANATOMY
MYOCARDIAL INFARCTION
 With sudden occlusion of a major artery by an
embolus (G. embolus, plug), the region of
myocardium supplied by the occluded vessel becomes
infarcted (rendered virtually bloodless) and
undergoes necrosis (pathological tissue death).
 The three most common sites of coronary artery
occlusion and the percentage of occlusions involving
each artery are
 Anterior IV (LAD), branch of the LCA (40-50%).
 RCA (30-40%).
 Circumflex branch of the LCA (15-20%).

160.  An area of myocardium that has undergone necrosis constitutes a myocardial
infarction (MI).
 main cause of ischemic heart disease is coronary artery insufficiency, resulting
from atherosclerosis
 The atherosclerotic process, characterized by lipid deposits in the intima (lining
layer) of the coronary arteries, begins during early adulthood and slowly results
in stenosis of the lumina of the arteries .

161. CLINICAL ANATOMY
 Angina Pectoris
◦ Pain that originates in the heart as
the result of ischemia of the
myocardium
 Coronary Bypass Graft
◦ Bypassing site of coronary artery
obstruction
◦ GSV, Radial artery commonly used

162. GREAT VESSELS
164

163. Pulmonary trunk
 It conveys deoxygenated blood from the right ventricle to the lungs
 It is about 5 cm in length and 3 cm in diameter
 It is the most anterior of the cardiac vessels
 Below the aortic arch level with the T5 vertebra and to the left of
midline, it divides into right and left pulmonary arteries of almost equal
size
 This bifurcation lies below, in front and to the left of the tracheal
bifurcation.
165

164. The brachiocephalic veins
 Are formed posterior to the sterno clavicular
joints by the union of the Internal jugular and
subclavian veins.
 The left brachiocephalic vein is more than
twice as long as the right vein because it
passes from the left to the right side, passing
over the anterior aspects of the roots of the
three major branches of the arch of the aorta
 At the level of the inferior border of the 1st
right costal cartilage, the brachiocephalic veins
unite to form the SVC.
166

165. The superior vena cava
 Returns blood from all structures
superior to the diaphragm,
except the lungs and heart.
 It passes inferiorly and ends at
the level of the 3rd costal
cartilage, where it enters the
right atrium of the heart.
 Lies in the right side of the
superior mediastinum,
anterolateral to the trachea and
posterolateral to the ascending
aorta.
167

166. The Inferior vena cava
– BeginsanteriortotheL5 vertebraby theunion ofthe common
i
l
i
a
cveins.
– ascends on the r
i
g
h
tsideof thebodies oftheL3-L5vertebrae and on
ther
i
g
h
tpsoas major tothe r
i
g
h
tof theaorta.
– leavestheabdomen by passingthrough thecavalopening in the
diaphragm and entersthe thorax attheT8 vertebrallevel

167.  The overall length of the IVC i
s22 cm, greater than that
of the abdominal aorta
 The IVC collectspoorly oxygenated blood from the lower
limbs and non-portal blood from the abdomen and pelvis.
 Almost a
l
lthe blood from the digestive tracti
scollected by
the hepatic portal system and passes through the hepatic
veins to the IVC.

168. Great Vessels
 Aorta
◦ has 3 parts
 Ascending aorta
 Arch of aorta
 Descending aorta

169. Ascending aorta
 5 cm long, covered in the pericardium
 Begin behind left half of sternum at level of 3rd costal cartilage
 Ends at the level of right 2nd costal cartilage
 Has three dilations – right, left & posterior aortic sinuses
◦ right and left coronary arteries arise from right & left
aortic sinuses

170. Arch of aorta
 Exclusively located in the superior mediastinum
 Begin in right 2nd costal cartilage, directs upward, backward and to the
left
 Ends at the lower border of T4 to be continuous with the descending
aorta.
 Curves above the root of lung behind left primary bronchus
 Branches
◦ Brachiocephalic trunk
 It divides in to right common carotid artery and right subclavian
arteries
◦ Left common carotid artery
◦ Left subclavian artery

171. Arch of aorta

172. The brachiocephalic trunk
 Is the first & largest branch of the arch of aorta
 Arises posterior to the manubrium, where it is anterior to the trachea
and posterior to the left brachiocephalic vein
 It ascends superolaterally to reach the right side of the trachea and the
right sterno clavicular joint, where it divides into the right common
carotid and right subclavian arteries.
174

173. The left common carotid artery
 Is the second branch of the arch of the aorta
 Arises posterior to the manubrium, slightly posterior and to the left of
the brachiocephalic trunk
 Ascends anterior to the left subclavian artery and is at first anterior to
the trachea and then to its left
 Enters the neck by passing posterior to the left sterno clavicular joint
175

174. The left subclavian artery
 Is the third branch of the arch of aorta
 Arises from posterior part of the arch of aorta, just posterior to the left
common carotid artery
 Ascends lateral to the trachea and left common carotid artery through
the superior mediastinum
 It has no branches in the mediastinum
 As it leaves the thorax and enters the root of the neck, it passes
posterior to the left SC joint
176

175. Descending Thoracic Aorta
 Continuation of the arch of aorta
 It arises in the posterior mediastinum
 Begins on the left side of the lower border
of the body of T4
 Terminates at lower border of T12 where it
passes through the aortic hiatus
 Lies posterior to the root of the left
lung pericardium, and esophagus
 Posteriorly related with vertebral column &
hemiazygos vein

176. Descending Thoracic Aorta
 Branches
◦ Right & left posterior intercostal arteries
for 3rd -11th intercostal spaces
◦ Right and left subcostal
◦ two left bronchial arteries
◦ esophageal arteries (to middle 1/3rd)
◦ Pericardial branches
◦ Mediastinal branches
◦ Right and left superior phrenic

177. CLINICAL ANATOMY
Coarctation of the Aorta
 In coarctation of the aorta, the arch of the aorta or descending aorta
has an abnormal narrowing (stenosis) that diminishes the caliber of
the aortic lumen, producing an obstruction to blood flow to the inferior
part of the body
 The most common site for a coarctation is near the site of the ductus
or ligamentum arteriosum.
179

178. Coarctation of the Aorta
 When the coarctation is post ductal , a good collateral circulation
usually develops between the proximal and distal parts of the aorta
through the intercostal and internal thoracic arteries
 Postductal coarctation is compatible with many years of life because
the collateral circulation carries blood to the thoracic aorta inferior to
the stenosis.
180

179. 181

180. Thank you!