The document summarizes the arterial and venous anatomy of the brain. It describes the major arteries that supply blood to the brain, including the internal carotid, vertebral, and basilar arteries. It discusses the circle of Willis and territories supplied by the anterior, middle, and posterior cerebral arteries. It also outlines the dural venous sinuses and cerebral veins that drain blood from the brain. Key structures mentioned include the cavernous sinus and superior sagittal sinus.

1. BLOOD SUPPLY OF BRAIN
Dr Srikanth

2. Normal vascular anatomy of brain
 Comprises of
 1.Arterial supply
 2.Venous drainage

4. Carotid artery
 External carotid artery
 Superior thyroid artery
 Ascending pharyngeal artery
 Lingual artery
 Occipital artery
 Posterior auricular artery
 Superficial temporal artery
 Internal maxillary artery
 Internal carotid artery
 Carotid bulb
 Cervical segment
 Petrous segment
 Lacerum segment
 Cavernous segment
 Clinoid segment
 Ophthalmic segment
 Post communicating
artery

5. Internal carotid artery

8. CIRCLE OF WILLIS

10. Anterior cerebral artery :-
 The anterior cerebral artery is the more medial branch of
supraclinoid ICA.the ACA runs mostly in the
interhemispheric fissure and has three distinct segments.

11. A1.(HORIZONAL)ACA SEGMENT
 Branches:
 MEDIAL LENTICULOSTRIATE ARTERY-pass superiorly
through anterior perforated substance to supply medial
basal ganglia
 RECURRENT ARTERY OF HEUBNER-arise from distal
A1 or promixal A2 and curves backward above horizontal
ACA,joins medial lenticulostriate arteries to supply
inferomedial basal ganglia,and anterior limb of internal
capsule.

13. ACA SEGMENTS cont….
 A2(vertical)segment-courses superiorly in the
interhemispherical fissure extending from A1-AcoA
junction to corpus callosum rostrum .
 It has two cortical branches,the orbitofrontal and
frontopolar that supply the undersurface and
inferomedial aspect of frontal lobe.

14. A3(callosal)segment
 curves anteriorly around
corpus callosum genu
 Divides into two terminal
ACA branches
 1.pericallosal-larger one
,runs posteriorly between
dorsal surface of corpus
callosum and cingulate
gyrus.
 2.callosomarginal arteries-
courses over the cingulate
gyrus within cingulate
sulcus.

15. Vascular territory of ACA
 cortical branches supply
anterior two thirds of
medial hemisphere and
cc,the inferomedial suface
of frontal lobe and the
anterior two thirds of
cerebral convexity adj to
the interhemispheric
fissure.
 The penintrating ACA
branches (mainly the
medial lenticulostriate
arteries)supply the medial
basal ganglia,cc genu
anterior limb of internal
capsule

16. Middle cerebral artery
 Large ,more lateral terminal branch of
supraclinoid ICA
 4 segments:-
(1) Horizontal segment(M1)-extends laterally from
ICA bifurcation towards sylvian fissure (lateral
cerebral) fissure.it bifurcates or trifurcates
before entering sylvian fissure.
Branches-
1.Lateral lenticulostriate arteries-supply lateral
putamen,caudate nucleus and external capsule
2. anterior temporal artery-supply tip of temporal

18. Middle cerebral artery cont….
 M2(INSULAR)segment-
 The post bifurcation MCA
trunk turn posterosuperiorly
in sylvian fissure following a
gentle curve or genu(knee)
 Arise from post bifurcation
trunks and sweep upward
over the surface of insula.
 M3(opercular)segment-
branches loop at the top of
sylvian fissure then course
laterally under the parts
(opercula)of the frontal
,parietal and temporal lobes
that hang over and enclose
the sylvian fissure

20.  M4(CORTICAL)segmen
t-MCA becomes M4
when it exits the sylvian
fissure and ramify over
the lateral surface of
cerebral hemisphere

21. Vascular territories of MCA
 MCA supplies most of
lateral surface of
cerebral hemisphere
,only a small thin strip at
the vertex is supplied by
ACA,and occipital and
posteroinferior parietal
lobes supplied by PCA
.its penintrating branch
supply mostly lateral
basal brain structure.

22. Posterior cerebral artery
 The two posterior cerebral arteries are two major terminal
branches of distal basilar artery
 4 segments
 P1(precommunicating)segment
 1.the thalamoperforating arteries
 Corses posterosuperiorly in the interpeduncular fossa to
enter the underface of midbrain

24. Posterior cerebral artery cont
 P2 (ambient)
 Two major cortical branches –
 Anterior temporal artery
 Posterior temporal artery
 These arise from P2 segment and pass laterally towards
inferior surface of temporal lobe.
 Small branches-
 Thalmoperforating artery
 Peduncular perforating artery

25. P2 segment cont….
 Medial posterior
choroidal artery(PchA)
 Curves around
brainstem courses
superomedially to enter
tela choroidea and roof
of 3rd ventricle
 Lateral posterior
choroidal artery(PchA)
enters lateral ventricle
and travels with choroid
plexus curves around
pulvinar of thalamus

26.  P3(QUADRIGEMINAL)SEG
MENT-.it begins behind the
midbrain and ends where
the PCA enters the
callcarine fissure of occipital
lobe
 P4 (calcarine)segment-
terminates within the
calcarine fissure where it
divides into two terminal
PCA trunks.
 the medial trunk gives off the
 medial occipital artery
 ,calcarine artery
 posterior splenial artery
 The lateral trunk –
 Lateral occipital artery

27. Vascular territory of PCA
 Supplies most of inferior
surface of cerebral
hemisphere with the
exception of the temporal
tip and frontal lobe
 Also supplies occipital
lobe ,posterior one third of
the medial hemisphere
and corpus callosum and
most of choroid plexus
 Penintrating PCA
branches are the major
vascular supply of mid
brain and posterior
thalami.

28. Vertebrobasilar system
 Vertebro basilar system consists of:-
 2 vertebral arteries
 The basilar artery

29. Vertebral Artery Anatomy
Vertebral Artery extend -
 First branch of the Subclavian
 Arises from the upper and back of the first part of the Subclavian Artery
 Ascends in foramina in the transverse processes of the upper six cervical
vertebrae
 Winds behind the superior articulating surface of the atlas
 Enters the skull through the foramen magnum
 Unites at the lower border of the pons with the artery of the opposite side to
form the Basilar artery

31. Vertebral Artery (V1,V2,v3,v4 segments)
Divided into 4 segments
 V1(extraosseous): unnamed segmental arteries
 V2(foraminal): anterior meningeal artery aries from it
 V3(extraspinal ): posterior meningeal artery arises from it
 V4 (intradural)segment
 Branches
 1.Anterior spinal artery
 2.posterior spinal arteries
 3.medullary perforating branches
The posterior inferior cerebellar artery (PICA)arise from distal VA curves
around over the tonsil and gives off perforating branches like-
Medullary
Tonsillar
Inferior cerebellar

33. Basilar artery
Basilar Artery
 Formed by the junction of the two vertebral arteries at pontomedullary
junction
 BA courses superiorly in prepontine cistern lying between clivus in front
and pons behind
 Tereminates in interpeduncular fossa by dividing into the two posterior
cerebral arteries

35. Basilar artery branches
 BRANCHES:
 Anterior inferior cerebellar
artery(AICA)
 Superior cerebellar arteries
 Pontine
 labyrnthine
 Vascular territory
 The vertobasilar system supplies all
the posterior surface fossa structure
as well as midbrain ,posterior
thalami,occipital lobes,most of the
inferior and posterolateral surface of
the temporal lobe and upper cervical
spinal cord .

36. Circle of willis
Arterial anastomostic ring that surrounds the basal brain
structure and connects the anterior and posterior circulation
with each other
10 components-
Two ICA
Two proximal or horizontal (A1)anterior cerebral
artery(ACA)segment.
Anterior communicating artery (AcoA)
Two post communicating arteries (PcoA)
The basilar artery(BA)
Two proximal or horizontal (P1)segments of the(PCA)

38. End of arterial system

39. Venous drainage of brain
 Intracranial venous system has
 Two components
 Dural venous sinuses
 The cerebral veins

40. Dural venous system
Anteroinferior group
• Cavernous sinuses
• Superior petrosal
sinuses
• Inferior petrosal sinuses
• Clival venous plexus
• Sphenoparietal sinus
Posterosuperior group
• Superior sagittal sinus
• Inferior sagittal sinus
• Straight sinus
• Sinus confluence
(torcular herophili)
• Transverse sinus
• Sigmoid sinus
• jugular bulbs

41. Dural sinus cont…
 Dural sinuses and venous
plexuses
 Endothelium lined channels
contained between the
outer(periosteal)
 And inner (meningeal)dural
layers.
 Contains arachnoids
granulations(AG) also known
as pacchionian granulations
and contains CSF
 A central core of CSF extends
from subarachnoid space
(SAS) into the granulations
covered by an apical cap of
arachnoid cells
 Multiple small channels extend
through full thickness of the cap
to sinus endothilium and drains
CSF into venous circulation

42. Superior sagittal sinus
 Large ,curvilinear sinus parallels the inner calvarial
vault.
 Originates from ascending frontal veins anteriorly
and runs in midline at the junction of falx cerebri with
calvaria ,its diameter increases posteriorly,and
associated with no of superficial cortical veins that
drains into diploic space ,and large anastomosing
vein of trolard
 Coronal section –appears triangular vascular
channel contains between dural leaves of falx
cerebri

44. Inferior sagittal sinus
 Smaller than sss.lies bottom of falx cerebri
 And abv corpus callosum and cingulate gyrus
,collecting small tributaries as it curves posteriorly
along inferior free margin of falx
 The ISS terminates at the falcotentorial junction
where it joins with great vein of galen to form straight
sinus

46. Transverse sinus
 Contained between attachment of tentorium cerebelli
to inner table of skull.
 curve laterally from trocular to posterior border of
petrous temporal bone where they turn inferiorly and
become sigmoid sinus

47. Straight sinus
 Straight sinus formed by ISS and great cerebral vein
of galen.
 Runs posteroinferiorly from origin at falcotentorial
apex.recieves tributaries from falx cerebri and
tentorium cerebelli.
 Terminates by joining superior sagittal and
transverse sinuses to form venous sinus
confluence(torcular herophili)

48. Sigmoid sinuses and jugular bulbs
 Inferior continuations of the two transverse
sinuses.(s shape curve)descending behing petrous
temporal bone to terminate becoming internal jugular
veins
 The jugular bulbs are focal venous dilation at the
skull base between sigmoid sinuses and extracranial
internal jugular veins(IJV)

50. Cavernous sinus
 Irregularly shaped heavily trabeculated/compartmentalized
venous sinuses lie along the side of sella turcica ,extending
from superior orbital fissure anteriorly to clivus and petrous
apex posteriorly.
 Formed by a thin medial dural wall contains-
 Two cavernous internal carotid arteries(ICA)
 And abducens( CN VI)
 CN III,IV,V1,V2 are actually within lateral dural wall and not
inside CS proper.
 Major tributaries draining
 Ophthalmic vein
 Sphenoparietal sinuses


52.  The cs communicates with each other by
intercavernous venous plexuses.
 Drain inferiorly through foramen ovale into pterygoid
venous plexus
 Posteriorly clival venous plexus also superior and
inferior petrosal sinus

53. Superior and inferior petrosal sinus
 Superior petrosal sinus-courses posterolaterally
along top of petrous temporal bone extending from
CS to sigmoid sinus
 Inferior petrosal sinus –courses just abv
petrooccipital fissure from inferior aspect of clival
venous plexus to jugular bulb

54. Clival venous plexus
 It’s a network of connected venous channels extends
along dorsum sellae superiorly to foramen
magnum.it connects cavernous and petrosal sinuses
with each other with suboccipital veins around
foramen magnum.
Sphenoparietal sinus
 Courses around lesser sphenoid wing at rim of
middle cranial fossa .receives superficial veins from
anterior temporal lobe and drains into cavernous or
inferior petrosal sinus.

55. CEREBRAL VEINS
 Subdivided into three groups
1)superficial/ cortical/ external veins
2) deep/internal veins
3) Brain stem/posterior fossa veins

56. Superficial cortical veins
 It consists of
1)Superior group
2) Middle group
3) Inferior group

57. Superior cortical veins
 Superior cortical veins
 8 to 12 superficial veins
course over upper surface
of cerebral hemisphere
following convexity
sulci,cross subarachnoid
space pierce arachnoid
and inner dura before
draining SSS.
 A dominant superior
cortical vein the vein of
trolard courses upward
from sylvian fissure to join
SSS

58. Middle cortical vein
 Prominent is the superficial middle cerebral
vein.begins over sylvian fissure and collects
numerous small tributaries from temporal frontal,and
parietal opercula that overhang the lat cerebral
fissure

59. Inferior cortical vein
 Drain most of inferior frontal lobes and temporal
poles
 The deep middle cerebral vein collect tributaries
from insula ,basal ganglia,and parahippocampal
gyrus then anastomoses with basal vein of
rosenthal.
 it courses postrosupereiorly in the ambient cistern
curving around mid brain to drain into v of G
 Posterior anastomosing vein i.e., vein of labbe
courses inferolaterally over temporal lobe to drain
into transverse sinus .

61. Deep cerebral vein
 Divided into 3 groups
 1. medullary veins
 2.subependymal veins
 3.deep paramedian vein

62. Medullary vein
 Originate one or two cm below the cortex and course
straight through the white matter towards the ventricle
where they terminate in subpendymal veins
 Subependymal veins
 Course under ventricular ependyma,collecting blood from
basal ganglia and deep white matter(via medullary vein)
 Important subependymal veins are septal veins and
thalamostrate veins.
 Septal veins –curve around frontal horn of 4th
ventricle.courses posteriorly along septum pellucidi.
 Thalamostraite veins-receive tributaries from caudate
nuclei and thalami curving medially to unite with septal vein
near foramen of monroe to form two internal cerebral vein.

63. Deep paramedian vein
 Internal cerebral vein(ICV)and vein of galen (VofG)
 Paired paramedian veins that courses posteriorly in
cavum velum interpositum ,the thin invagination of
subarachnoid space lies between 3rd ventricle and
fornices.the ICV s terminate in the rostral quadrigeminal
cistern by uniting with each other to form of VofG.the vein
of galen curves posterosuperiorly under corpus callosum
splenium uniting with iss to form straight sinus.

64. Brainstem /posterior fossa veins
 Divided
 1.SUPERIOR GALENIC GROUP
 2.ANTERIOR(PETROSAL)GROUP
 3.POSTERIOR GROUP
 Superior galenic group
 Drain sup into vein of galen
 Major vein of this group
 Precentral cerebellar vein
 The superior vermian vein
 Anterior pontomesencephalic vein

65. Precentral cerebellar vein
 Single midline vein lies between lingula and central
lobule of vermis terminates behind inferior colliculi by
draining into VofG.the superior vermian vein runs
over top of vermis,joining PCv and draining into VofG
 Anterior pontomesencephalic vein
 Interconnected venous plexus covers the cerebral
peduncles and extends over anterior surface of pons

66. Anterior petrosal group
posterior (tentorial group)
 Large venous trunk lies in cerebellopontine angle
cistern collecting numerous tributaries from
cerebellum ,pons and medulla
 Posterior (tentorial group)
 Inferior vermian vein (the most prominent
vein).,paired paramedian structure that curve under
the vermis and drain inferior surface of cerebellum.

67. Pattern of venous drainage
1)Peripheral venous drainage
 Radical pattern
 Mid and upper surfaces of cerebral hemisphere together
with their subjacent white matter drain centrifugaly
(outward)via cortical veins of SSS
2)Deep(central)brain damage
 Basal ganglia thalami,most of interspheric white matter
drain centripetally(inward)into deep cerebral veins.the
internal cerebral vein ,vein of galen and straight sinus drain
entire central core of brain.
 Most area of temporal lobes the uncus and anteromedial
hippocampus drain into galenic system via deep middle
cerebral veins and basal veins of rosenthal.

68. 3)Inferolateral(perisylvian)drainage
 Parenchyma surrounding sylvian(lateral cerebral)fissure
consist of frontal ,parietaland temporal opercula plus insula
 This perisylvian drain via superficial middle cerebral vein
into sphenoparietal sinus and cavernous sinus.
4) Posterolateral(temoroparietal)drainage
 The posterior temporal lobes and inferolateral aspect of
parietal lobes drain via superior petrosal sinuses and
anastomosing vein of labbe into transverse sinuses.

70.  THANK YOU