Middle cerebral artery

The middle cerebral artery (MCA) is one of the three major paired arteries that supply blood to the brain. The MCA arises from the internal carotid artery (ICA) as the larger of the two main terminal branches (MCA and anterior cerebral artery) coursing laterally into the lateral sulcus where it branches and provides many branches that supply the cerebral cortex.

Gross anatomy

Segments

The MCA is divided into four segments:

  • M1: from the origin to bifurcation/trifurcation (the limen insulae); also known as horizontal or sphenoidal segment
  • M2: also known as insular segment, from bi(tri)furcation to circular sulcus of insula where it makes hairpin bend to continue as M3
  • M3: opercular branches (those within the Sylvian fissure); also known as opercular segment
  • M4: branches emerging from the Sylvian fissure onto the convex surface of the hemisphere; also known as cortical segment
Branches
M1
M2

Division of the MCA is variable after the horizontal segment, although most commonly, it divides into two trunks-superior and inferior:

  • 78% bifurcate into superior and inferior divisions
  • 12% trifucate into superior, middle and inferior divisions
  • 10% branch into many smaller branches
Superior terminal branch
Inferior terminal branch
  • three temporal branches (anterior, middle, posterior)
  • branch to the angular gyrus
  • two parietal branches (anterior, posterior)
Supply

The middle cerebral arteries supply the majority of the lateral surface of the hemisphere, except the superior portion of the parietal lobe (via ACA) and the inferior portion of the temporal lobe and occipital lobe (via PCA). In addition, they supply part of the internal capsule and basal ganglia.

In its territory lie the motor and sensory areas excluding leg and perineum and auditory and speech areas.

Variant anatomy

  • MCA duplication-reported incidence of ~1.5% (range 0.2-2.9%); parallels the main MCA and supplies the anterior lobe
  • accessory MCA
  • MCA fenestration is rare with a report incidence of <1%
  • early branching of the MCA-bi/trifurcation occurs within 1 cm of origin

Neuroanatomy
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Article Information

rID: 4522
Section: Anatomy
Synonyms or Alternate Spellings:
  • MCA
  • Middle cerebral artery (MCA)

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Cases and Figures

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    Figure 1: basilar artery and circle of Willis
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    Figure 2: cerebral arterial supply to the brain
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    Figure 3: cortical vascular territories
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    Figure 4: Cerebral vascular territories
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    Figure 5: MCA lateral
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    Figure 6: MCA frontal
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