The MCA is the largest and most complex of the cerebral arteries. It arises from the internal carotid artery and has four segments - M1, M2, M3, M4. The M1 segment can be further divided into pre-bifurcation and post-bifurcation parts. Early branches and perforating arteries originate from the M1 segment. The MCA has a variable branching pattern and anomalies include duplication, accessory branches, and fenestration. Key angiographic landmarks include the Sylvian point and Sylvian triangle.

1. MCA Anatomy
-Dr Dikpal

2. Introduction
• The MCA is the largest and most complex of
the cerebral arteries
• The MCA arises as the larger of the two
terminal branches of the internal carotid
artery
• The diameter of the MCA at its origin ranges
(average, 3.9 mm), roughly twice that of the
anterior cerebral artery

3. Its origin and course

4. Post
medial

7. Segments
•M1 (sphenoidal),
•M2 (insular),
•M3 (opercular),
•M4 (cortical)

10. M1 segment
• Microneurosurgical and
angiographic
• Prebifurcation and post
bifurcation parts
• How to distinguish between early
branches and M1

11. Branching pattern M1

12. Early branches
• Cortical Branches from main trunk
proximal to MCA division
• types
• early temporal branches- more
common
• early frontal branches

18. Perforating branches
• Lenticulostraite arteries - branches of MCA that
enter anterior perforating substance (APS)
• origin from superior or posterosuperior MCA
• 3 groups : medial, intermediate and lateral
• MEDIAL: least constant, 1-5 branches from M1, enter
medial APS
• INTERMEDIATE: constant, few branches dividing,
atleast 1 major artery
• LATERAL: constant S shaped course, enter
posterolateral part of APS

25. Cortical branches

28. Anomalies of MCA
• Rare compared to other intracranial
arteries
Main anomalies include
• duplication
• accessory
• fenestration

30. Anatomy of the Middle Cerebral Artery: Cortical Branches, Branching Pattern and Anomalies; Karen CILLIERS, Benedict John PAGE; DOI:
10.5137/1019-5149.JTN.18127-16.1

31. Angiographic Sylvian Point (ASP)
• It is the most medial point where the last
cortical MCA branch (usually the angular
artery) turns inferiorly to exit the sylvian
fissure.(On AP view)
• This point approximates the apex of the insula
and represents the posterior limit of the
lateral cerebral sulcus.

33. Sylvian triangle (angiographic)
• The superior insular line ( A line tangent to the
tops of the insular loops),
• Main MCA trunk ( forms the posterior inferior
margin of the triangle)
• Most anterior branch of the ascending frontal
complex ( forms the anterior border of the
triangle)
• It is seen in lateral view and serves as angiographic
landmark for localizing supratentorial masses.

36. • Round shift = Frontal lesion anterior to coronal
suture
• Square shift = Lesion behind foramen of Monro
in lower half of hemisphere
• Distal shift = Posterior to coronal suture in
upper half of hemisphere
• Proximal shift = Basifrontal lesion / anterior
middle cranial fossa including anterior temporal
lobe

37. Exposing MCA

38. Sylvian fissure