Easy approach

1. Presenter: Dr. Nikhil panpalia
Guide: Dr.K.R.Naik

2.  Understanding vascular anatomy is fundamental
to neuroimaging.
 About 18% of the total blood volume in the body circulates in
the brain, which accounts for about 2% of the body weight.
 The blood transports oxygen, nutrients, and other substances
necessary for proper functioning of the brain tissues and carries
away metabolites.
 Loss of consciousness occurs in less than 15 seconds after
blood flow to the brain has stopped, and irreparable damage to
the brain tissue occurs within 5 minutes.
 Cerebrovascular disease or stroke, occurs as a result of
vascular compromise or haemorrhage and is one of the most
frequent sources of neurologic disability.

3.  Part 1 –
 Aortic arch and great vessels
 Carotid arteries
 Circle ofWillis
 Part 2 –
 Cerebral arteries
 Posterior fossa arteries – vertebrobasilar system

4. 1. Conventional intra-arterial angiography – DSA
system - techniques of image acquisition
 Standard radiographic projections
 carotid angio-
▪ Lateral projection – centered on pituitary fossa
▪ AP view – with petrous ridge projected over the roof of orbit
▪ I/L anterior oblique – for aneurysms in SAH
 Vertebral angio –
▪ lateral , half-axial (Towne’s) and AP – petrous ridge superimposed
on lower border of orbit
2. Computed tomography angiography
3. Magnetic resonance angiography
4. Doppler ultrasound

5. Starts from aortic arch :
Aortic arch
Innonimate or
brachiocephalic
artery
Left common
carotid
Left subclavian
Brachiocephalic
or innonimate
Rt common
carotid
Rt subclavian

6. 3 . Innonimate artery
10. Left subclavian
artery
15. Left common
carotid artery

7. 4. Right subclavian
artery
5. Right common
carotid artery

8. Right subclavian artery
Right
vertebral
artery
Internal
mammary artery
Thyrocervical
trunk
Costocervical
trunk

9. 6. Right vertebral artery
9. Internal mammary artery
16.Thyrocervical trunk
16

10.  Common arch anomaly
 0.5-1% of all cases
 Here it is the last brachiocephalic
vessel arising from aortic arch -4th
branch
 Often asymptomatic – 10 % of
people can have dysphagia lusoria.
 Right common carotid arises
directly from arch – first branch

11. Barium studies – fixed narrowing of
esophagus at the level of arch
without mucosal deformity –
bayonet deformity

12.  1st Branch of right subclavian artery
 Right vertebral artery dominant -25%
 Anomalous origin – uncommon

13.  Arises from proximal brachicephalic
 Only cervical part as it arises caudally

14.  RCCA – directly from aortic arch ( when right
SCA is aberrant )
RCCA
RSCA

15.  2nd major branch from aortic arch
 Thoracic and cervical part –in thoracic it travels upwards throu superior
mediastinum to the level of left sternoclavicular joint and continues as
cervical
15.Left common
carotid
CCA bifurcates into ICA and ECA
at midcervical level C3-C6 level.

16. LCCA- common
origin with IA

17.  LCCA – hypoplastic
or absent – here the
ECA and ICA arise
directly from aortic
arch

18.  Last branch from aortic arch
 Major branches -
Left subclavian artery
Left vertebral
artery
Internal
mammary
Thyrocervical
trunk
Costocervicalt
runk

19.  First branch of left subclavian artery
 Dominant in 50-60%
 In 25% right and leftVA are equal in size
11.Left vertebral artery
14.Left internal mammary

20.  Left vertebral artery –directly from aortic arch -5%
( nondominant )

21. RSCA
LSCA
Innominate
artery
LCCA
RCCA
RVA
LVA

22.  Course - Runs within a fascial
plane – the carotid sheath –
also contains IJV and vagus
nerve( vein lateral to artery ,
nerve between the two)
(VNA)
 Runs obliquely upwards from
the level of sternoclavicular
joint to the level of thyroid
cartilage
 Bifurcates at the level of C3-
C5 into external and internal
carotid artery
 At bifurcation ICA usually lies
posterior and lateral to the
ECA

23.  Smaller of the 2 carotids.
 Origin anterior and medial to ICA.
 Supplies the extracranial structures.
 Branches –( Sister Lucy’s Powdered Face Attracts
SO Many Medicos )
Internal carotid artery
External carotid artery
Common carotid artery

24. External carotid artery
Anterior
Superior
thyroidal (sister)
Lingual (lucy)
Facial (face)
Posterior
Occipital
Posterior
auricular
(powdered)
Medial
Ascending
pharyngeal
(attracts)
Terminal
Maxillary (many)
Superficial
temporal (so)

25. ECA – branches

26. Superior thyroid artery
Lingual artery
Facial artery
Occipital artery
Posterior auricular
artery
Ascending pharyngeal
artery
Early arterial phase of CCA angiogram

27. Late arterial phase of CCA angiogram
Posterior auricular
artery
Occipital artery
Facial artery
Lingual artery
Superficial temporal
artery
Maxillary artery
Transverse facial

28.  Internal maxillary artery-
 Runs forward deep to the
mandible.
 Branches – inferior alveolar,
middle meningeal, deep
temporal , accessory
meningeal , sphenopalatine ,
infraorbital , descending
palatine, muscular branches.
 Middle meningeal artery –
runs superiorly crosses STA on
lateral projection thro
foramen spinosum.
 Supplies – dura and inner
table of skull.

29.  On angiogram should be
differentiated from middle
meningeal artery –
characteristic hairpin turn of
STA over zygomatic process
 Supplies –part of scalp and
ear.
 Branch – transverse facial
artery
 Variant –TFA may arise from
ECA directly
STA
Middle meningeal artery
hairpin turn of STA

30. Oblique view – MRA
Vertebral artery
Thyrocervical trunk
Facial artery
Lingual artery
Superficial
temporal artery
Occipital artery
Maxillary artery

31. Straight AP view – MRA
Superficial
temporal artery
Hairpin turn of
STA
Maxillary artery
Facial artery
Lingual artery
Vertebral artery
Middle meningeal
artery

32. Left CCA
Right CCA
Internal carotid- carotid
bulb
ECA
3-D CTA
• Origin -Lateral to
ECA.
• Can be divided into
number of segments
between the bulb and
its bifurcation into
MCA and ACA.

33. Cervical
Intraosseous /
petrous
Lacerum
Cavernous
Intracranial /
supraclinoid
Opthalmic
Communicating

34. ICA
Carotid bulb
Petrous
Cavernous
Supraclinoid
Cervical
Oblique DSALateral DSA

35.  Distal 2-4 cm of CCA
 Bulbous dilatation of ICA
origin
 Thinner media and thicker
adventitia containing many
receptor endings of
glossopharyngeal nerve

36.  No narrowing
 No dilatation
 No branches
 No tapering
Course – crosses
behind and
medial to ECA
ICA
ICA
ECA

37.  10%- ICA
originates medial
to ECA
 Anomalous ECA
branches arises
from cervical ICA
 Persistent
embryonic vesels
may anastomose
with
vertebrobasilar
system
ICA
ECA

38. Vertical
•Short vertical segment – anterior to IJV
•Genu – petrous ICA turns anteromedially in front of cochlea
•Longer horizontal segment
ICA –intraosseous
1. enters carotid canal in
petrous temporal
bone.
2. Surrounded by
sympathetic plexus
3. exit at petrous apex
Horizontal
Genu

39. Petrous segment of ICA
• Branches supply middle earIntrapetrous
• Inconstant
• Throu Foramen lacerum and vidian
canal
• Anastomose with branches of ECA
(Recurrent br of greater palatine)
Vidian artery
(artery of Pterygoid
canal )
• Important branch –tympanic cavity
• Supplies middle and inner ear
Corticotympanic artery

40. Axial NECT inferior to superior ( bone window )

42. Aberrant course
•Posterolateral course thro temporal bone
•Vertical segment of carotid canal absent
Normal course of ICA
•Anteromedial course thro temporal bone
•3 segments

43. Rare- 0.48%
Intrapetrous embryonic vascular
channel.
Origin – petrous ICA
Course – passes throu the
footplate of stapes.
Termination – as middle meningeal
artery
CT- absentI/Lforamenspinosum
d/d – glomus tumor
Recognised before surgery

44. Small segment that extends from petrous apex above foramen lacerum curving upwards
and then becomes the cavernous segment
Covered by trigeminal ganglion
No branches

45. Carotid angiogram

46. C4 segments
1. Ascending (posterior vertical )
2. Posterior genu
3. Horizontal
4. Anterior genu
5. Anterior vertical
Branches
Meningohypophyseal artery
Inferolateral trunk
Small capsular branches
Starts from petrous apex
Terminates at its entrance into
intracranial subarchnoid space adjacent to
anterior clinoid process.
Covered by trigeminal ganglion
posteriorly.

47. Carotid
angiogram

48. Axial CT
Posterior genu as it courses
anteromedially into the
cavernous sinus
ICA courses along the
bony grooves of carotid
sulcus along the
basisphenoid bone
•Throu cavernous sinus proper turns superiorly
• Form grooves under anterior clinoid process
• Anterior genu of ICA .
• Curve upwards towards dural ring
• Enter subarchnoid space
Posterior genu
Carotid sulcus
Anterior genu

50. Menigohypophyseal artery
•Posterior trunk
•Arises at junction of c4 and
c5
•Supplies –
•pituitary gland
•tentorium
•cavernous sinus
• clival dura
• CN 3 , 4
•Enlarges to supply dural
vascular malformation /
neoplasm
Inferolateral trunk
• Lateral mainstream artery
• Arises – inferolaterally
from c4 segment
• Supplies –
• CN 3,4,6
• gasserian ganglion CN5
• cavernous sinus dura
• Anastomose with br of
internal maxillary artery .
• Enlarged – vascular
neoplasm / malformation
/ collaterals to ECA

51. •Starts distal ly to cavernous sinus
•Ends as near anterior clinoid
process
•No important branches

52. Extends from superior
clinoid to just below
posterior
communicating artery
(PCoA) origin
Branches –
•Opthalmic artery
•Superior hypophyseal
artery
CECT
Anterior clinoid process C6

53. Origin –
• Intradural
•Antero-superior ICA
• Medial to anterior clinoid process
Course –
Anterior throu optic canal
Below optic nerve
Crosses superomedially over the nerve
Supply -globe
Gives off ocular , lacrimal , muscular branches
•Anastomose with ECA

54. Mid arterial phase DSA
Lateral view MRA
Lateral DSA

55. Arises from posteromedial aspect of
supraclinoid ICA
Course – across the ventral surface of
optic chaisma
Terminates- pituitary stalk and gland
Supplies – anterior pituitary ,
Infundibulum , optic nerve and chaisma
Anastomose - with hypophyseal branch
from the contralateral ICA forms plexus –
superior hypophyseal plexus
DSA – usually not visualized if not
enlarged

56. •Extends from below PCoA to
terminal ICA bifurcation.
•Passes between optic and
occulumotor nerve.
C7 segment branches
Posterior communicating artery Anterior choroidal artery
Lateral DSA
AChA
PCoA
3D CTA

57. •Arises – posterior aspect of
intradural ICA just below
anterior choroidal artery
•Course – posterolaterally
above the occulumotor nerve
to join posterior cerebral
artery
•Branches – anterior
thalamoperforating arteries
•Supplies – optic chiasma,
pituitary stalk , thalamus ,
hypothalamus.
Lateral late
arterial DSA
MRA

58. 1. Hypoplasia – 1/3 rd cases
2. PCoA duplication/ fenestraion –
rare
PCoA fenestration
PCoA hypoplasia

59. • PCoM is larger than P1 segment of PCA and supplies the bulk of PCA . PCA therefore
is a part of anterior circulation

60. •Infundibular dilatation of PCoA
at origin from ICA- 5-15%
•Should be 2 mm or less
•Funnel shaped , conical
•PCoA arises from apex

61. Within suprasellar cistern under optic tract
Posteromedially around temporal lobe uncus
Cisternal Course :
Intraventricular course:
AChA angles sharply laterally
Enters choroidal fissure of temporal bone
Abrupt kink – plexal point
AChA-origin few mms above PCoA
Cisternal segment
Intraventricular segment

62. Supplies
Choroidal plexus of lateral ventricle (
temporal horn and atrium )
Optic tract and cerebral peduncle
Uncal and parahippocampal gyri of
temporal lobe .
Thalamus and posterior limb of internal
capsule.
Anastamoses – with AChA segments and
LPChA and MPChA
Variants – uncommon
Aplasia rare
Hypoplasia – 3 %
Hyperplasia – 2.3 %
AP mid arterial DSA
AP Late arterial DSAMRA lateral view
Choriodal
blush

63. Terminal ICA
Anterior cerebral artery Middle cerebral artery
3D CTA
MCA
ACA
ICA
3D CTAMid arterial phase DSA

65. Maxillary artery
• Middle meningeal
artery
• Foramen rotundum
artery
• Accessory meningeal
• Vidian artery
• Ant / mid deep
temporal
ICA
• Ethmoidal br of
opthalmic artery
• Inferlolateral trunk of
ICA
• Inferolateral trunk
• Intratemporal ICA
• Opthalmic artery

66. • Occipital
• Ascending pharyngeal
artery
• Ascending pharyngeal
artery
• Facial artery
• Posterior auricular
artery
• Vertebral
• Vertebral C3 level
• ICA (petrous and
cavernous )
• ICA (opthalmic artery)
• ICA (stylomastoid
artery)

67. 2ICAs
Horizontal segment A1
of both ACAs
2 Posterior
communicating arteries
Anterior
communicating artery
Horizontal segment P1
of both PCA s
Basilar artery

68. Interconnected arterial
polygon
Location – surrounds
ventral surface of
diencephalon,
adjacent to optic nerve and
tracts, inferolateral to
hypothalamus
Anterior
circulation
2 B/L ICAs
2ACAs
UnpairedACoA
anteriorly
Posterior
circulation
Basilar bifurcation
from mergedVAs
2PCAs from BAs
B/L PCoAs

69. 3DVRT CTA MRA
CT MRA
1. A1
2. P1
3. PCoA
4. ACoA

70. • Medial lenticulostriate arteries
• Recurrent artery of HeubnerACAs
• Perforating branches – hypothalamus , optic
chiasma , cingulate gyrus , corpus callosum , fornix
• Large vessel – median artery of corpus callosum
arises from ACoA
ACoA
• Anterior thalamoperforating arteriesPCoA
• Posterior thalamoperforating arteries
• Thalamogeniculate arteries
Basilar artery,
PCAs
Supplies-
1.Optic
chiasma and
tracts
2.Infundibulum
3.Hypothalam
us
4.Base of
brain

71.  Complete COW –only 20 –
25%
 Posterior circle anomalies –
50% anatomy specimens
Common variants
•Hypoplasia of 1 or both PCoA
– 34%
•Fetal origin of PCA from ICA

72. •Hypoplasia or absent A1 ACA
segment.
•Absent , duplicate or
multichannelACoA – 10-15%

73.  Represent persistent embryonic
circulatory patterns
 Channels between caudal carotid
artery and paired basilar and
vertebral arteries fail to regress.
1. Primitive persistent trigeminal artery
2. Primitive hypoglossal artery
3. Persistent otic artery
4. Proatlantal intersegmental artery
PCoA
PTA
Otic
Hypoglossal
Proatlantal
intersegmental

74. •Most common carotid vertebro basilar anastomoses - 0.1- 0.6%
•In utero – embryonic trigeminal artery supplies basilar artery before the PCoA and vertebral
artery develops
•As these vessels enlarge – PTA normally disappears
course – arise when ICA exists carotid canal and enters
cavernous sinus
Runs posterolaterally along trigeminal nerve 41%
Crosses over / throu dorsum sella before joining
basilar artery
Connects ICA to vertebrobasilar system trident shape on lateral DSA

75.  2nd most common- 0.027-
0.26%
 .
 Intracranial aneurysms
 If present – single artery that
supplies brain stem and
cerebellum
Courses thro hypoglossal canal
Parallel to CN 12
Connects cervical ICA with basilar
artery

76. Red – PHA Blue – sigmoid sinus Pink – coil mass with basilar tip
aneurysm

77.  Origin – petrous ICA
 Course – medially thro internal
auditory meatus and joins caudal
basilar artery
 VA – hypoplastic / absent – POA is the
sole arterial supply to basilar artery
Basilar artery
POA

78.  Cerebral arteries
 Vertebral artery
 Basilar artery

79. Distal ICA
Anterior cerebral
artery
Middle cerebral
artery
Basilar artery
Posterior
cerebral artery

80. A1 horizontal
segment
• From ACA origin to
ACoA junction.
• Inferior br – supply
superior surface of optic
nerve and chaisma.
• Superior br – anterior
hypothalamus , septum
pellucidum , anterior
commisure , fornix ,
anterior inferior portion
of corpus straitum.

81. Arise fromA1 segment-
perforating branches.
• Pass cephalad
thro anterior
perforated
substance.
• Supply head of
caudate nucleus
and anterior limb
of IC, putamen .

82. • Largest of the perforating
branches.
• May arise fromA1 or A2
segment.
• A1 – 44%
• Proximal A2 – 50%
• ACoA – less common
• Derives its name from the
fact that it doubles back on
its parent artery at an acute
angle to join
lenticulostriate vessel.
• Lies parallel to A1 .

83. From ACoA junction
Ascend in front of 3rd ventricle in cistern
of lamina terminalis
br –Orbitofrontal, frontopolar
Curves around corpus callosum genu
gives terminal branches
A2 terminal
branches-
Pericollasal
Collasomarginal

84. • Supply the anterior 2/3rds
of medial hemispheric
surface + small superior
area over the convexities.
• Callosomarginal a.– lies in
cingulate gyrus supplies
medial frontal lobe
• Pericallosal a.– course
along the posterior aspect
of corpus callosum and
supplies it and medial
parietal lobe

85. Lateral DSA mid arterial phase
A1
A2
A3
orbitofrontal
Callosomarginal
Pericollasal
Medial lenticulostriate
Recurrent
artery
heubner
Pericollasal
A2
Orbitofrontal
Frontopolar
A3
Callosomarginal
AP DSA mid arterial
3D MRA
A2
Pericollasal
Callosomarginal

86.  ACA – ACoA complex – normal 1/3rd anatomy
dissection
 Absent , duplicate or multichannelACoA –
10-15%

87. • Hypoplasia or absent A1 ACA segment-distal
segments fill preferentially from other side via ACoA.

88.  Fenestration /
duplication of
ACA

89. M1 horizontal
Origin -Laterally from ICA
bifurcation
Till its bi/trifurcation at sylvian
fissure.
Br – Lateral Lenticulostriate
branch course superiorly
Anterior temporal artery
Supplies-Lentiform nucleus
Part of IC , caudate nucleus
M2 insular
At its genu divides
into branches
Loop over insula pass
laterally to exit from
sylvian fissure
M3 opercular
Emerge from
sylvian fissure
Ramify over
hemispheric surface
Supplies –cerebral
cortex and white
matter

92. 1. Orbitofrontal artery (lateral
frontobasal )
2. Prefrontal arteries
3. Precentral (prerolandic )
4. Central sulcus (rolandic)
5. Postcentral sulcus (anterior
parietal) artery
6. Posterior parietal artery
7. Angular artery
8. Posterior temporal
9. Temporooccipital artery
10. Medial temporal

93. AP DSA mid arterial phase
AP DSA early arterial phase

94. Early arterial phase
Lateral DSA Mid arterial phase

95. Lateral
•M1 horizontal
•MCA bifurcation
•M2 insular
•M3 opercular
CT

96. MRA

97. • Origin - M1
• Supplies –
• Part of head
and body of
caudate
• Globus pallidus
• Putamen
• Posterior limb
of internal
capsule

98. • Supplies
• Inferolateral
frontal lobe
• Insular cortex
• Parietal lobe
• Temporal lobe

99. Supplies –
• Lateral
cerebrum
• Insula
• Ant- lateral
temporal
lobe

100.  Less frequent
 Fenestration and duplication
 Single trunk
 Accessory arteries
All uncommon
≤5 %

102. • It is either hypertrophied RA heubner or medial ACA perforator.
• To be called accessory MCA it should have cortical branches.

103. PCA origin from bifurcation of basilar artery in interpeduncular cistern.
Lies above occulomotar nerve.
Circles midbrain above tentorium cerebelli.

104. P1 precommunicating /
peduncular
• Basilar bifurcation extends
laterally
• Junction with PCoA
• Br –
• Post thalamoperforating-
thalamus , midbrain
• Medial posterior choroidal
artery – anteromedially along
roof of 3rd ventricle –tectal
plate , midbrain , thalamus
posterior , pineal gland , tele
choroidae of 3rd ventricle.
P2 ambient / crural
• PCA- PCoA junction posterior
• Above trochlear nerve and
tentorial incisura
• Br –
• Thalamogeniculate arteries-
MGB , pulvinar , brachium
superior colliculus , crus
cerebri , LGB
• Lateral post choroidal artery –
over pulvinar of thalamus –
posterior thalamus , lateral
ventricular choroid plexus

106. P3 quadrigeminal
Behind midbrain in quadrigeminal
plate cistern
Reciprocal relationship with MCA
Inferior temporal artery
• Undersurface of temporal bone
• Anastamose -MCA
Parietooccipital artery
• Posterior 1/3rd interhemispheric
surface
• ACA
Calcarine artery( P4 )
• Visual cortex
• Occipital pole
Posterior pericollasal artery
(splenial)
• Splenium of corpus callosum
• ACA

107. AP DSA
AP DSA mid arterial
phase

108. Early arterial
phase
Lateral DSA Mid
arterial phase

109. MRA
CTA

110. • Supply –
• Medial +posterior
temporal lobe
• Medial parietal
lobe
• Occipital lobe

111.  Fetal origin of PCA from ICA instead of basilar – 15- 20 %
 Carotid basilar anastomosis – supply PCA via trigeminal artery or
other persistent channels

112. V1 Courses –Cephalad to enter
transverse foramina at C6
Ascend directly to C2 (V2)
Turns laterally and superiorly thro
C1 vertebral foramina
Looping posteriorly along atlasV3
extraspinal
EachVA passes superomedially
thro foramen magnum
In Posterior fossa
anterior to medulla (intradural )
VAs unite to form basilar artery
From subclavian arteries
LeftVA dominant 50%

113. Vertebral artery
Anterior spinal artery
Joins ASA from oppositeVA
along anteromedial sulcus of cervical
cord.
Medial medullary syndrome
Posterior inferior cerebellar
artery
Arises from distalVA
Lateral medullary syndrome

115. Lateral DSA
AP DSA
V1- extraosseous
V2 –foraminal
V3 – extraspinal
V4 – intradural

116. • Front of medullaAnterior medullary segment
• Along side of medulla caudally to level of CN 9-11Lateral medullary segment
• Around inferior half of cerebellar tonsilTonsilomedullary segment
• Cleft btw tela choridae and inferior medullary velum rostrally
and superior pole of tonsil caudallyTelovelotonsillar segment
Cortical / hemispheric
segment

117. Lateral DSA early
arterial
Lateral DSA
late arterial

119. Anterior medullary segment
Posterior medullary segment
Lateral medullary segment

120. •Choroid plexus of 4th
ventricle.
•Posterolateral medulla.
•Cerebellar tonsil.
•Inferior vermis.
•Posteroinferior cerebellar
hemisphere.
Supplies

121.  Persistent
vertebrobasilar
anastamosis
 LeftVA – aortic
arch origin – 5%
 HypolasticVA – 40
%
HypoplasticVA

122. VA terminates in PICA – 1%

123. Orange arrow –
duplicatedVA
Red – originalVA from
subclavian
VA duplication- ocassionally

124. VA fenestration –
occasionally

125. Extradural origin of PICA
PICA fromVA below foramen magnum

126. Right and leftVA s
unite – BA
Course cephalad in front of
pons
Pontine cistern in the
space delineated by
lateral margin of clivus
and dorsum sellae
Terminates in
interpeduncular cistern
Divides into PCAs
•Average length – 3 cm
•Width 1.5- 4 mm
•Diameter <4.5 mm

127. 1. AICA – Anterior Inferior
CerebellarArtery
 1st major branch.
 Posterior laterally in
cerebellopontine angle cistern
toward the internal auditory canal.
Here typically anteroinferior to
facial and vestibulocochlear nerve.
 Few mms from origin AICA crossed
by abducens nerve.
 Supplies-
▪ Nerves
▪ Inferolateral pons
▪ Middle cerebellar peduncle
▪ Flocculus
▪ Anterolateral cerebelllar hemisphere

128. 2. SCA- SuperiorCerebellar
Artery –
 Arises from BA apex.
 Posterolaterally around Pons
and mesencephalon below
tentorial incisura and CNS 3 n
4.
 Supplies –
▪ Superior surface of vermis n
cerebellar hemisphere.
▪ Deep cerebellar white matter.
▪ Dentate nucleus.
 Perforating branches – short
n long segment
 BA – terminates into PCA s

129. AP DSA

131. MRA

135. SCAs- can
arise from P1
segment

136.  Osborne radiology
 Gionni Boris bradac –Cerebral angiography