Anatomy of the middle cerebral artery (MCA) from the neuroradiology point of view. Important for Neuroradiologists and Neurointerventionalists.

1. Interventional Neuroradiology
Anatomy
Middle Cerebral Artery (MCA)
Mohamed M.A. Zaitoun, MD
Interventional Radiology Consultant, Zagazig University Hospitals, Egypt
FINR-Switzerland
zaitoun82@gmail.com
Interventional Radiology Unit,
Zagazig University, Egypt

3. Knowing as much as possible
about your enemy precedes
successful battle and learning
about the disease process
precedes successful
management.

4. Middle Cerebral Artery (MCA)
1-Origin
2-Segmental Anatomy
3-Branching Pattern
4-Branches
5-Anomalies

5. 1-Origin :
-The MCA arises as the lateral terminal
branch of the ICA
2-Segmental Anatomy :
a) M1 :
-Horizontal , from the ICA to the lateral
fissure

6. b) M2 :
-Insular , the upper & lower trunk arteries
thus formed
-Designates the branches located inside the
Sylvian fissure (to the top of the Sylvian
fissure) , extends from the genu to the
circular sulcus of the insula
c) M3 :
-Opercular , denominates the branches
located between the top of the Sylvian
fissure and the cerebral cortex

7. d) M4 :
-Cortical , refers to arterial branches on the surface
of the cerebral cortex
-Angular artery is often described as the
continuation of the MCA because it lies in the
center of this candelabrum of branches when
viewed on lateral angiography , it exits from the
posterior limit of the sylvian fissure and is
therefore a landmark for mapping the sylvian
triangle of vessels (a useful tool used by pre-CT
Neuroradiologist to decide if a mass is originated
in the temporal or frontal lobe)

12. (1) MCA bifurcation (genu) , (2) MCA (M1) , (3) ICA (RT side) , (4) ACA
(A1) , (5) ICA (LT side) , (6) MCA (LT side)

13. (1) MCA , M4 , (2) MCA (M3) , (3) MCA (M2) , (4) MCA
(M1) , (5) ICA (LT side) , (6) MCA (LT side)

14. (1) MCA (M4) , (2) MCA (M3) , (3) MCA (M2) , (4) MCA (M1) , (5) LT
ICA , (6) LT MCA , (7) Basilar artery , (8) PCA

15. -2D frontal view following right ICA
injection , the appearance of the
carotid circulation is normal , Note the
early bifurcation of MCA (normal
variant)
1 ICA – cervical segment
2 ICA – vertical petrous segment
3 ICA – horizontal petrous segment
4 presellar (Fischer C5) ICA
6 horizontal (Fischer C4)
intracavernous ICA
9 ophthalmic artery
10 & 11 proximal and distal
supraclinoid segment ICA
12 posterior communicating artery
13 anterior choroidal artery
14 internal carotid artery bifurcation
15 A1 segment of ACA
17 recurrent artery of Heubner
20 proximal A2 segment ACA
21 callosomarginal branch ACA
28 pericallosal branch of ACA
31 M1 segment of MCA
32 lateral lenticulostriate arteries
33 bifurcation/trifurcation of MCA
34 anterior temporal lobe branches of
MCA
35 orbitofrontal branch of MCA
43 sylvian point
44 opercular branches of MCA
45 sylvian (insular) branches of MCA

16. -Frontal 3D view following right
internal
carotid artery injection , these views
show the normal appearance of the
intracranial internal carotid artery
circulation. The proximal A2 segments
of the anterior cerebral arteries have
been intentionally removed from the
images
1 ICA – cervical segment
2 ICA – vertical petrous segment
3 ICA – horizontal petrous segment
4 presellar (Fischer C5) ICA
6 horizontal (Fischer C4)
intracavernous ICA
8 anterior genu (Fischer C3)
intracavernous IAC
9 ophthalmic artery
10 & 11 proximal and distal
supraclinoid segment ICA
13 anterior choroidal artery
14 ICA bifurcation
15 A1 segment of ACA
20 proximal A2 segment ACA
22 orbitofrontal branch of ACA
31 M1 segment of MCA
33 bifurcation/trifurcation of MCA
43 sylvian point
44 opercular branches of MCA
45 sylvian (insular) branches of MCA

17. -Lateral 2D view following
CA injection in the late arterial phase
-The triangle placed on the image is
called the sylvian triangle , this
represents the geometric
representation of the MCA overlying
the insular cortex
-Alteration in the shape of this triangle
can indicate mass displacements of
the (MCA) branches
1 ICA – cervical segment
2 ICA – vertical petrous segment
3 ICA – horizontal petrous segment
4 presellar (Fischer C5) segment ICA
6 horizontal (Fischer C4)
intracavernous ICA
8 anterior genu (Fischer C3)
intracavernous ICA
9 ophthalmic artery
35 orbitofrontal branch of MCA
36 operculofrontal branches of MCA
37 pre-central branch(es) of MCA
38 central rolandic branches of MCA
39a anterior parietal branch of MCA
39p posterior parietal branch of MCA
40 angular artery
42m middle temporal branches of
MCA
42p posterior temporal branches of
MCA
43 sylvian point
44 opercular branches of MCA

18. 3-Branching Pattern :
-The MCA can divide in up to four described
patterns : a single trunk with no main division
, a bifurcation , a trifurcation or a
quadrifurcation
-Of these , the most common is a bifurcation
pattern seen in 64% to 90% of hemispheres
-The terminology of superior and inferior
divisions of the MCA is widely used in the
clinical practice
-A trifurcation pattern may be seen in 12% to
29% of hemispheres with other patterns
being less common

19. -The relative positions of the upper & lower
trunks can be difficult to distinguish on 2D
imaging , but it is important to recognize
that the lower trunk branches contribute to
the posterior part of the territory (and
therefore it is the usual origin of the
angular artery) , since the upper trunk
supplies the anterior part of the territory
(i.e. frontal lobe & a variable amount of the
temporal lobe)

20. a) Inferior division dominance >>
-It is slightly more common (32 %) for the
inferior division to be dominant covering a
more extensive cortical area than the
superior division
-When the inferior division is dominant , it
covers the temporal and parietal lobes
with the superior division confined to the
frontal lobe

21. Short M1 segment (red) with smaller superior division (yellow)
supplying the frontal convexity and larger inferior division (orange)
into the temporal lobe (purple , subdividing into black anterior and
white posterior temporal and white parieto-occipital) and parietal
lobe (blue) feeders

22. -The superior division (red) can be traced to the frontal
lobe (purple) , the inferior division (yellow) is
dominant

23. b) Superior division dominance >>
-The superior division is dominant in 28% of
hemispheres
-When the superior division is dominant , its territory
may extend as far posteriorly as the angular or
temporo-occipital regions
-These configurations have clinical relevance , in the
dominant hemisphere , the clinical syndrome of a
dominant superior division occlusion might include
parietal lobe signs such as finger agnosia , the
Gerstmann syndrome of left-right disorientation ,
acalculia , agraphia , hemineglect and impairment
of discriminative sensation

24. Frontal DSA of the MCA bifurcation in a patient with a dominant upper
trunk shown in 2D (a) & 3D reconstruction on (b) , the upper trunk
branches supply the anterior portion of the MCA territory

25. c) Balanced division >>
-Balanced division is seen in approximately
18% of hemispheres , in which cases , the
superior division spans the orbitofrontal to
the posterior parietal areas

26. -2D frontal view following right ICA
injection , the appearance of the
carotid circulation is normal , Note the
early bifurcation of MCA (normal
variant)
1 ICA – cervical segment
2 ICA – vertical petrous segment
3 ICA – horizontal petrous segment
4 presellar (Fischer C5) ICA
6 horizontal (Fischer C4)
intracavernous ICA
9 ophthalmic artery
10 & 11 proximal and distal
supraclinoid segment ICA
12 posterior communicating artery
13 anterior choroidal artery
14 internal carotid artery bifurcation
15 A1 segment of ACA
17 recurrent artery of Heubner
20 proximal A2 segment ACA
21 callosomarginal branch ACA
28 pericallosal branch of ACA
31 M1 segment of MCA
32 lateral lenticulostriate arteries
33 bifurcation/trifurcation of MCA
34 anterior temporal lobe branches of
MCA
35 orbitofrontal branch of MCA
43 sylvian point
44 opercular branches of MCA
45 sylvian (insular) branches of MCA

27. 4-Branches :
-Can be classified into two groups :
a) Deep (perforator)
b) Superficial (cortical)

28. a) Deep (Perforating) Branches :
-Arise from the superior surface of the M1
segment
-They are grouped as the medial & lateral
lenticulostriate arteries which pierce the
anterior perforating substance , lateral
lenticulostriate arteries supply the lateral
portion of the putamen and external
capsule as well as the upper internal
capsule , medial lenticulostriate arteries
supply the globus pallidus and medial
portion of the putamen

30. -2D frontal view following left ICA
injections , these images show an
aneurysm in the region of the left MCA
bifurcation/trifurcation
2 ICA – vertical petrous segment
3 ICA – horizontal petrous segment
4 presellar (Fischer C5) ICA
6 horizontal (Fischer C4) intracavernous
ICA
8 anterior genu (Fischer C3)
intracavernous ICA
9 ophthalmic artery
10 & 11 proximal and distal supraclinoid
segments ICA
12 PCOM
13 anterior choroidal artery
14 ICA bifurcation
15 A1 segment of ACA
18 A1-A2 junction ACA
20 proximal A2 segment ACA
21 callosomarginal branch of ACA
22 orbitofrontal branch of ACA
28 pericallosal branch of ACA
31 M1 segment of MCA
32 lateral lenticulostriate arteries
33 bifurcation/trifurcation MCA
34 anterior temporal lobe branches MCA
35 orbitofrontal branch MCA
43 sylvian point
44 opercular branches MCA
45 sylvian (insular) branches MCA

31. -2D frontal view following right ICA
injection , these views show a small
aneurysm projecting inferiorly in the
region of the right MCA bifurcation
1 ICA – cervical segment
2 ICA – vertical petrous segment
3 ICA – horizontal petrous segment
4 presellar (Fischer C5) segment ICA
8 anterior genu (Fischer C3)
intracavernous ICA
9 ophthalmic artery
10 & 11 proximal and distal
supraclinoid segments ICA
13 anterior choroidal artery
14 ICA bifurcation
15 A1 segment of ACA
18 A1-A2 junction ACA
20 proximal A2 segment ACA
21 callosomarginal branch of ACA
22 orbitofrontal branch of ACA
23 frontopolar branch of ACA
28 pericallosal branch of ACA
31 M1 segment of MCA
32 lateral lenticulostriate arteries
33 bifurcation/trifurcation of MCA
35 orbitofrontal branch of MCA
43 sylvian point
44 opercular branches MCA
45 sylvian (insular) branches of MCA
An aneurysm

32. b) Superficial (Cortical) branches :
-Supply a considerable proportion of the superficial
hemispheric cortex
-They follow the sulci of the brain and their description (and
relative size of each stem artery) depends on the
distances between branch points
*Arteries to the Frontal lobe :
-These run superiorly after leaving the fissure , from
anterior to posterior :
1-Orbitofrontal artery of the MCA
2-Prefrontal artery (supplies Broca’s area)
3-Precentral artery (or Pre-Rolandic artery of Sillon)
4-Central artery (or artery of the Rolandic fissure)

34. - Lateral 2D view following
internal carotid artery injection mid
arterial phase , non-filling of the anterior
cerebral artery allows for an unobtrusive
view of the more distal (mca) branches. A
template type
labeling of the distal middle cerebral
artery branches allows for greater
variability in the proximal branching
pattern of the mca vessels. Note the
choroidal blush along the posterior
margin of the globe (eye)
1 internal carotid artery – cervical
segment
2 internal carotid artery – vertical
petrous segment
3 internal carotid artery – horizontal
petrous segment
4 presellar (Fischer C5) segment
internal carotid artery
6 horizontal (Fischer C4)
intracavernous
segment internal carotid artery
8 anterior genu (Fischer C3)
intracavernous segment ICA
10 & 11 proximal and distal
supraclinoid segments internal
carotid artery

35. *Arteries to the Parietal & Occipital lobes:
-These run posterior to the sylvian fissure ,
from superior to inferior :
1-Anterior parietal
2-Posterior parietal
3-Angular
4-Occipito-temporal

36. 1-Orbitofrontal , 2-Prefrontal , 3-Precentral , 4-Central , 5-Anterior parietal , 6-
Post parietal , 7-Angular , 8-Occipito-temporal , 9-Posterior temporal , 10-
Middle temporal , 11-Anterior temporal , 12-Tempero-polar

37. *Arteries to the Temporal lobe :
-These run inferiorly after leaving the lateral
sulcus of the sylvian fissure and are
arranged from anterior to posterior :
1-Temporo-polar
2-Anterior temporal
3-Middle temporal
4-Posterior temporal

38. 1-Orbitofrontal
2-Pre-rolandic
3-Rolandic
branches
4-Anterior and
posterior parietal
branches
5-Anterior temporal
6-Middle temporal
7-Posterior
temporal
8-Occipito-temporal

39. -Anterior temporal branch (best seen in AP view) , a typical
appearance of an anterior temporal branch of the MCA
proximal to the main bifurcation is indicated with the
arrow

41. **N.B. :
-Cortical arteriolar-arteriolar anastomoses exist
between branches of the anterior and posterior
cerebral arteries and between the distal
branches of the MCA
-They are often seen in patients with occlusion of
the proximal MCA and become more reliable ,
as collateral support to the cortex , it occlusions
are more distal to the first branch point (i.e. MCA
bifurcation) , though there is obviously a limit to
how distal embolization can be tolerated in any
tree

42. 5-Anomalies :
a) Incidence :
-Anomalies of MCA are more rare than those of
the other intracranial vessels
-They are seen in approximately 0.6% to 3% of
dissected hemispheres in microanatomical
studies , but less commonly during
angiography
-These anomalous vessels may be prone to
aneurysm formation

43. b) Types :
1-Rare instances of fenestrations
2-Duplications arising from the ICA
3-An accessory MCA from the ACA (Although
the accessory MCA may have lenticulostriate
branches , it is distinguished from a recurrent
artery of Heubner by the fact that it has a
predominantly cortical distribution , moreover
, it has been seen during dissections to be
distinct from Heubner's artery)

44. Fenestrations of the MCA , 2 cases show a variable appearance of fenestration
of the proximal M1 segment (arrowheads) , in these patients , it is an
inconsequential finding , however , when endovascular treatment of a
nearby lesion is planned , the presence of an anomaly such as this can be
very significant , fenestrations of the vertebrobasilar junction are associated
with a high risk of aneurysm formation but fenestrations of the MCA are so
uncommon that an association with aneurysmal formation is not known

45. Duplicated middle cerebral arteries , (a) A temporal branch of the RT MCA
territory (arrow) has its origin from the supraclinoid internal carotid artery ,
distinguishing this vessel as a duplicated MCA , an incidental finding in this
patient , it would , however, be important to clarify such an anomalous
finding with the surgeon if treatment of an adjacent aneurysm were
contemplated , (b) A similar anomaly is seen (arrows) from the left internal
carotid artery in this different patient

46. Accessory LT MCA , a 35 years old female with multiple aneurysms
demonstrates an accessory left MCA (arrows) arising from the
distal A1 segment , such vessels and the recurrent artery of
Heubner on occasion are sometimes most distinctly seen during
the contralateral carotid injection because the remainder of the
ipsilateral middle cerebral artery is not then opacified

47. Duplicated RT MCA , a patient presenting with a SAH related to an aneurysm
of the ACOM (arrow) demonstrates a duplicated appearance of MCA
(arrowheads) , in effect , this is a very proximal bifurcating pattern of the
MCA but nevertheless constitutes an anomaly that might have specific
implications for patient treatment in various situations , note the mandibular
artery remnant (squiggly arrow) arising from the petrous segment

48. Bilateral accessory MCA , in this patient , an anomalous vessel
(arrowheads) to the MCA territory arises on each side from the A1-A2
region , qualifying as accessory middle cerebral arteries in each
instance , however , some authors would argue this vessel is only a
hyperplastic variant of the recurrent artery of Heubner

49. Accessory MCA from the A1 segment , a middle-aged patient was
having ischemic symptoms in the right hemisphere , at angiography
, the only lesion explaining her symptoms was this stenosis (arrow)
at the origin of this accessory MCA variant