2. Embryology
• Heart is first seen in the form of two endothelial heart tubes-
18th day of foetal life
• Fusion results in a single tube with a series of
dilatations(Bulbus cordis, Ventricle, Atrium,Sinus venosus)
and begins to beat by 22nd day
3. • Ventricle and atrium
are connected by a
narrow atrio-
ventricular canal.
• The sinus venosus has
prolongations that are
referred to as its right
and left horns.
4. • Bulbus cordis represents
arterial end of the tube-
Proximal -- No special name
Middle -- Conus
Distal -- Truncus arteriosus
5. • Truncus continues with the aortic sac from which right
and left pharyngeal arch arteries arises
• They arch backward on lateral side of foregut –continues
as right and left dorsal aorta-fuse to form descending
aorta
6. • Sinus Venosus
1. Lies at the venous end of
the heart
1. Right and Left horns-
- Vitelline vein
- Umbilical vein
- Common cardinal vein
8. • First arteries to appear are right and left Primitive Aorta connected to the two
endocardial heart tubes
Parts of Primitive Aorta-
1. Ventral aorta-Ventral to foregut
2. Arched portion-connected to first pharyngeal arch
3. Dorsal aorta-Dorsal to foregut
9. • After the fusion of endocardial heart tubes,ventral aorta fuse
to form Aortic Sac
• Unfused parts remaining as the right and left horns of the sac
10. • During 4th and 5th
week,successive arterial arches
appear in 2nd to 6th pharyngeal
arches
• Each connects ventrally to aortic
sac & dorsally to dorsal aorta
12. • 3rd and 4th open to ventral part of aortic sac
• 6th open to dorsal part of aortic sac
• Spiral septum formed in truncus arteriousus in the 5th
week extends to aortic sac, fuses with posterior wall-
-Blood from pulmonary artery goes to 6th arch artery
-while from ascending aorta passes into 3rd &4th arch
arteries.
13.
14.
15. • Two dorsal aortae grow
cranially, beyond the point
of attachment of the first
arch artery
16. • Portion of dorsal aorta b/w 3rd
and 4th (ductus
caroticus)disappear
17. • Portion of the right dorsal
aorta, which lies between
the point of attachment of
the fourth arch artery and
the point of fusion of the
two dorsal aortae,
disappears
18. • Each 6th arch artery connects
to the pulmonary vascular
tree
• Portion between this
connection and dorsal
aorta(Ductus
Arteriosus)regresses on right
side
• Ductus Arteriosus is
obliterated after birth and is
then seen as the ligamentutn
arteriosum.
19. • Each third arch artery gives off a bud that grows cranially
to form the external carotid artery
20. • Dorsal aorta gives lateral intersegmental
branches to body wall.7th cervical
intersegmental supplies upper limb bud
21. • The ascending aorta and the pulmonary trunk are formed
from the truncus arteriosus
22. • The arch of the aorta is derived from the ventral part of
the aortic sac (1), its left horn (2), and the left fourth arch
artery (3)
23. • The descending aorta is derived from the left dorsal aorta,
below the attachment of fourth arch artery (1), along with
the fused median vessel (2)
25. (A) The right subclavian artery is derived (1) from the right 4th arch artery and {2)
from the right 7th cervical intersegmental artery. The left subclavian artery is
formed only from the left 7th cervical intersegmental artery.
(B) The common carotid artery is derived from the proximal part of the 3rd arch
artery.
(C) The internal carotid artery is derived from (1) distal part of the 3rd arch artery
and (2) dorsal aorta (cranial-most part).
26. (A) The external carotid artery arises as a bud from the 3rd arch artery.
(B) The pulmonary arteries arise from the 6th arch arteries.
(C) The ductus arteriosus is derived from part of the left 6th arch artery.
27. • As the right third and fourth arch arteries arise from the
right horn of the aortic sac, the common carotid and
subclavian arteries become branches of the
brachiocephalic artery.
• With the formation of the neck , and the descent
of the heart into the thoracic cavity ,
• The point of origin of the subclavian artery from
the aorta gradually shifts upwards and comes to
lie close to the origin of the Lt common carotid
artery
28.
29.
30. -The nerve of the sixth arch (recurrent laryngeal), is at first caudal to the artery of this arch
-on the right side, the nerve moves cranially and comes into relationship with the right
fourth arch artery (subclavian)
-On the left side, it retains its relationship to that part of the sixth arch which forms the
ductus arteriosus
31.
32.
33. AORTIC ARCH ANOMALIES
• DOUBLE ARCH
• RIGHT ARCH
• PATENT DUCTUS ARTERIOSIS
• ABERRANT RIGHT SUBCLAVIAN ARTERY
• INTERRUPTED AORTIC ARCH
• COARCTATION
• ANOMALOUS ORIGIN OF PULMONARY ARTERY
• ABNORMAL LEFT ARCH
• ABNORMAL RIGHT ARCH
• CERVICAL ARCH
34. EDWARD’S DOUBLE AORTIC ARCH
MODE
• Anomalies of aortic arch to be conceptualized as variations in
regression of different segments from a “hypothetical double arch”.
• The concept of “hypothetical double aortic arch” emphasises the
potential contribution of nearly all embryonic arches to components
of definitive arch system.
• Demonstrate possible embryologic explanations for each arch
anomaly.
35.
36. SIDEDNESS OF THE AORTA
• LEFT AND RIGHT ARCH REFERS TO WHICH
BRONCHUS IS CROSSED BY THE ARCH
37. • Occurs due to-
1. Some parts that normally disappear may persist
2. Some parts that normally persist may disappear.
38. Double Aortic arch
• Both right and left arches present.
• Both arches can be patent or one hypoplastic or atretic(usually
left)
• Persistence of both right and left 4th arch which join Truncus
arteriosus sac to their respective dorsal aortae
• Only one 6th remain.
• Form complete vascular rings.
• When both arches are patent, rings typically tight and present
with sridor in first week of life.
40. TRUNCUS ARTERIOSUS
• A single trunk arising from the heart
• 4 truncus and 2 conal cushions develop.
• Dextro- sinistro cushions of both conus and truncus fuse
to form Conotruncal septum
41. • Because the cushions
are dextro-superior and
sinistro inferior in
truncus and dextro-
dorsal and sinistro-
ventral in conus union
forms a spiral septum
than true lineal relation.
42. • Failure of aortopulmonary septum to Septation give rise to
persistent truncus arteriosus
43. CLASSIFICATION OF TRUNCUS
ARTERIOSUS
I) Edward & Collett classification-
• Type I – main pulmonary trunk arises from truncus arteriosus
and gives rise to RPA & LPA.
• Type II- RPA & LPA arteries arises directly and lying close
to one another.
• Type III- RPA & LPA arises from separate ostium lying at
some distance from one another.
• Type IV-absence of branch of PA ,pulmonary blood flow is
derived from aortopulmonary collaterals.
45. Aortopulmonary Window
-opening between ascending aorta and
pulmonary artery
-resulting from abnormal septation of the
truncus arteriosus into the aorta and
pulmonary artery
46. • . Classification
Type I : Between posteromedial wall of ascending
aorta and lateral wall of MPA
Type II : Between posterior wall of ascending aorta
and origin of RPA
Type III : Anomalous origin of RPA from postero-
lateral wall of ascending aorta
47. PATENT DUCTUS ARTERIOSIS
• The ductus arteriosus, which is normally occluded soon
after birth, may remain patent
• Communication between the pulmonary artery and the
aorta
48.
49. Type A - conical duct with well defined aortic ampulla and constriction near the
pulmonary artery end.
Type B - large duct with window like structure which is very short in length.
Type C - tubular duct without any constriction.
Type D - complex duct with multiple constrictions.
Type E - elongated duct with constriction remote from the edge of the trachea (as
viewed on lateral angiography)
50. COARCTATION OF THE AORTA
• Aorta may show a localized narrowing of its lumen
• May be distal to the attachment of the ductus (postductal)
• proximal to the attachment (preductal)- right ventricle
supplies the distal part of the body throug h the ductus
arteriosus
53. RIGHT AORTIC ARCH
MOST COMMON TYPES
• MIRROR IMAGE
• ABERRANT LEFT SUBCLAVIAN
• ISOLATED LEFT SUBCLAVIAN
54.
55. RIGHT AORTIC ARCH-MIRROR IMAGE
TYPE
• Sequence of arch vessels-left innominate,right
carotid.
• Ligamentum left sided.
• No vascular ring.
• Almost always associated with CHD (48% TOF)
57. Regression of the Right Fourth Arch Results in an
Aberrant Right Subclavian Artery
58.
59. • The ductus caroticus may persist. As a result, the left
internal carotid arises directly from the aortic arch, and the
right internal carotid from the subclavian
60. Anomalies in the pattern of the main branches of the arch of the aorta.
(A) Left common carotid arising from brachiocephalic artery.
(B) Left subclavian and left common carotid arising by a common stem (left brachiocephalic).
(C) Left vertebral artery arising directly from arch of aorta.
61. RIGHT AORTIC ARCH
MOST COMMON TYPES
• MIRROR IMAGE
• ABERRANT LEFT SUBCLAVIAN
• ISOLATED LEFT SUBCLAVIAN
62.
63. RIGHT AORTIC ARCH-MIRROR IMAGE
TYPE
• Sequence of arch vessels-left innominate,right
carotid.
• Ligamentum left sided.
• No vascular ring.
• Almost always associated with CHD (48% TOF)
65. INTERRUPTED AORTIC ARCH
Obliteration of the right and left fourth aortic arches
• Defined as complete separation of ascending
and descending aorta
• A segment of the aortic arch, may be missing
• ascending aorta ends by supplying the left
common carotid artery
• Left subclavian artery arises from the distal
segment which receives blood through a
patent ductus arteriosus.
66. Obliteration of the Right and Left Fourth Aortic
Arches Leads to Interruption of the Aorta
67. • Celoria and Patton classification(1959)
– Type A-interruption distal to SCA that is ipsilateral to 2nd carotid
artery
Type A-involution of both dorsal aorta distal to 4th
arch,prox to persistent 6th arch
– Type B-interruption b/w 2nd carotid and ipsilateral subclavian
Type b-involution of one 4th arch and one dorsal aorta b/w
4th and 6th
– Type C-interruption b/w carotids
Type C-involution of one limb of truncoaortic sac
68. Anomalous origin of pulmonary artery
from Ascending Aorta
• Anomalous pulmonary artery branch arising from ascending aorta in
presence of a MPA arising separately
• Anomalous RPA-
◦ More common
◦ Embryonic branch pulmonary artery joins right side of TA
sac, but fails the leftward migration to join MPA
before septation
• Anomalous LPA
◦ a/w TOF in 74%
◦ Embryonic branch pulmonary artery fails to join TA sac
69. Anomalous origin of LPA from RPA
• LPA arises from RPA and passes b/w trachea and esophagus-
Pulmonary artery sling.
70. LEFT AORTIC ARCH AND RETROESOPHAGEAL
DIVERTICULUM OF KOMMERELL
• First vascular ring to be diagnosed during life
• Similar to previous except for persistent 6th arch-
ligamentum which completes a vascular Ring
• Proximal RSCA dilated to form diverticulum
71. RIGHT AORTIC ARCH WITH RETROESOPHAGEAL
DIVERTICULUM OF KOMMERELL
• Sequence –left carotid, right carotid ,RSCA, a large
retroesophageal vessel( diverticulum) from which LSCA
arises
• Left ligamentum completes the ring
• Disappearance of Lt 4th arch and persistence of 6th arch
72. Abnormal Left Arch
• a) Left arch with retroesophageal RSCA
• b) Left aortic arch and retroesophageal
diverticulum of Kommerell
• c) Left aortic arch,right descending aorta,
right.ductus(circumflex aortic arch)
• d) Left aortic arch & isolated RSCA
• e) Left aortic arch with cervical origin of Rt subclavian
73. LEFT AORTIC ARCH,RIGHT DESCENDING AORTA,
RIGHT.DUCTUS(CIRCUMFLEX AORTIC ARCH
• Disappearance of right 4th arch but with left distal dorsal
aorta forming definitive distal arch and passing
retroesophageally to a descending aorta beginning to right
of vertebral column.
74. LEFT AORTIC ARCH & ISOLATED RSCA
• RSCA arises only from righ` t ductus.
• Right 6th arch persists with dossolution of right 4
th arch and right dorsal aorta.
75. LEFT AORTIC ARCH WITH CERVICAL ORIGIN OF
RIGHT SUBCLAVIAN
• Innominate trifurcates in the neck-RSCA travels back to
thorax
• Subclavian artery arises from 3rd arch in stead of 4 th .
• 3 rd arch being more cephalad gives origin to RSCA in
the neck.
76. • Dissolution of left dorsal aorta distal to the origin of left 7 th
intersegmental artery
• Left 4th arch becomes proximal left subclavian artery.
• Left Sixth arch persists- left ductus arises from underside of
left innominate artery and passes to LPA .
• Alternatively right ductus persists giving true mirror image
of normal
77. Persistent 5th Arch
• Double lumen aortic arch in which both arches appear on
same side of trachea.
78. RIGHT ARCH WITH LEFT DECENDING
AORTA & LEFT LIGAMENTUM
• Also known as circumflex right aortic arch.
• Embryology : Dissolution of either left dorsal aorta distal to
takeoff of the left subclavian artery or the left fourth arch.
Persistent left sixth arch connects to the left sided dorsal
aorta completing vascular ring .
• Aortic arch itself crosses midline to the left at the level of
T4 vertebral body -connects to left ductus to form vascular
ring
• Aortic arch is retroesophageal and not the subclavian artery.
79. RIGHT AORTIC ARCH WITH RETROESOPHAGEAL
INNOMINATE ARTEY
• Dissolution of left branch of truncoaortic sac and left 4th arch
• The left dorsal aorta supplies left 7th IS artery and left 3rd arch.
