1. The document describes the anatomy and branches of the major cerebral arteries including the anterior, middle, and posterior cerebral arteries. 2. It discusses the typical branching patterns and territories supplied by each artery and their segments. 3. Variations in arterial anatomy are also summarized such as fenestrations, duplications, hypoplasia.

1. Part 2
Dr Sameeha Khan

2.  Cerebral arteries
 Vertebral artery
 Basilar artery

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

4. 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.

5. Arise from A1
segment- perforating
branches.
• Pass cephalad
thro anterior
perforated
substance.
• Supply head of
caudate nucleus
and anterior
limb of IC,
putamen .

6. • Largest of the perforating
branches.
• May arise from A1 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 .

7. 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

8. • 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

10. 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

11.  ACoA -Part of COW -
not a true branch of ACA
 Branches – perforating
 Supply –Lamina terminalis ,
Hypothalamus , Anterior
commissure , Fornix, Septum
pellucidum , Para olfactory
gyrus , Subcellosal region ,
Anterior part of cingulate
gyrus

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

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

14.  Fenestration /
duplication of
ACA

15.  Single trunk from confluence of A1 segments of right n left ACAs-
supplies both hemispheres .
 Assc with lobar holoprosencephaly, saccular aneursym

16. • Normally A1
segment runs
over the optic
nerve.
• Here it runs
below the
optic nerve.
• Assc with
aneurysms .
• Recognised
before
surgeries.

17. Variable branches to C/L
hemisphere.
 Separate right n left ACA.
 1 ACA is dominant than
other and it sends
branches to other
hemisphere.
 Other ACA is hypoplastic
– terminate as
orbitofrontal or
frontopolar branch.

18. 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

21. 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

22. AP DSA mid arterial phase
AP DSA early arterial phase

23. Early arterial phase
Lateral DSA Mid arterial phase

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

25. MRA

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

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

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

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

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

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

33. 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

35. 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

36. AP DSA
AP DSA mid arterial
phase

37. Early arterial
phase
Lateral DSA Mid
arterial phase

38. MRA
CTA

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

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

41. 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 atlas
V3 extraspinal
Each VA passes superomedially
thro foramen magnum
In Posterior fossa
anterior to medulla (intradural )
VAs unite to form basilar artery
From subclavian arteries
Left VA dominant 50%

42. 1. V1-Small segmental
spinal/ meningeal/
muscular branches.
2. V2- Anterior Meningeal
artery , muscular
branches.
3. V3 -Posterior Meningeal
artery
 Courses along posterior
arch of atlas.
 Supplies falx cerebri
 Variant – origin from ECA
/ PICA.
 Greatly enlarged with
vascular malformations
and neoplasms Posterior meningeal artery

43. Vertebral artery
Anterior spinal artery
Joins ASA from opposite VA
along anteromedial sulcus of
cervical cord.
Medial medullary
syndrome
Posterior inferior
cerebellar artery
Arises from distal VA
Lateral medullary
syndrome

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

46. At c7 level At C6 level

47. At C1 C2 level At spinal cord and pons level

48. • Front of medulla
Anterior 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

50. Lateral DSA early
arterial
Lateral DSA
late arterial

52. Anterior medullary segment
Posterior medullary segment
Lateral medullary segment

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

54.  Persistent
vertebrobasilar
anastamosis
 Left VA – aortic
arch origin – 5%
 Hypolastic VA –
40 %
Hypoplastic VA

55. VA terminates in PICA – 1%

56. Orange arrow –
duplicated VA
Red – original VA
from subclavian
VA duplication- ocassionally

57. VA fenestration –
occasionally

58. Extradural origin of PICA
PICA from VA below foramen magnum

59. Right and left VA 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

60. 1. AICA – Anterior Inferior
Cerebellar Artery
 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

61. 2. SCA- Superior Cerebellar
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

62. AP DSA

64. MRA

68. SCAs- can
arise from P1
segment