Middle cerebral artery

Changed by Ian Bickle, 18 Jun 2017

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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 (the other being the 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 the horizontal or sphenoidal segment
M2: also known as the insular segment, from the bifurcation/trifurcation to the circular sulcus of the insula, where it makes a hairpin bend to continue as ~~tM3~~M3
M3: opercular branches (those within the Sylvian fissure); also known as the opercular segment
M4: branches emerging from the Sylvian fissure onto the convex surface of the hemisphere; also known as the cortical segment

Branches

M1

medial lenticulostriate penetrating arteries
lateral lenticulostriate penetrating arteries
anterior temporal artery
polar temporal artery
uncal artery (which may branch from the anterior choroidal artery)

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

lateral frontobasal artery
prefrontal sulcal artery
pre-Rolandic (precentral) and Rolandic (central) sulcal arteries

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 the ACA) and the inferior portion of the temporal lobe and occipital lobe (via the 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 temporal lobe
accessory MCA
MCA fenestration is rare with a report incidence of <1%
early branching of the MCA-bifurcation/trifurcation occurs within 1 cm of its origin

~~-<strong>M2: </strong>also known as the insular segment, from the bifurcation/trifurcation to the circular sulcus of the insula, where it makes a hairpin bend to continue as tM3</li>~~
+<strong>M2: </strong>also known as the insular segment, from the bifurcation/trifurcation to the circular sulcus of the insula, where it makes a hairpin bend to continue as M3</li>
-</ul><h5>Supply</h5><p>The middle cerebral arteries supply the majority of the lateral surface of the hemisphere, except the superior portion of the <a href="/articles/parietal-lobe">parietal lobe</a> (via the ACA) and the inferior portion of the <a href="/articles/temporal-lobe">temporal lobe</a> and <a href="/articles/occipital-lobe">occipital lobe</a> (via the <a title="PCA" href="/articles/posterior-cerebral-artery">PCA</a>). In addition, they supply part of the <a href="/articles/internal-capsule">internal capsule</a> and <a href="/articles/basal-ganglia">basal ganglia</a>.</p><p>In its territory lie the motor and sensory areas excluding leg and perineum and auditory and speech areas.</p><h4>Variant anatomy</h4><ul>
+</ul><h5>Supply</h5><p>The middle cerebral arteries supply the majority of the lateral surface of the hemisphere, except the superior portion of the <a href="/articles/parietal-lobe">parietal lobe</a> (via the ACA) and the inferior portion of the <a href="/articles/temporal-lobe">temporal lobe</a> and <a href="/articles/occipital-lobe">occipital lobe</a> (via the <a href="/articles/posterior-cerebral-artery">PCA</a>). In addition, they supply part of the <a href="/articles/internal-capsule">internal capsule</a> and <a href="/articles/basal-ganglia">basal ganglia</a>.</p><p>In its territory lie the motor and sensory areas excluding leg and perineum and auditory and speech areas.</p><h4>Variant anatomy</h4><ul>
-<a title="MCA duplication" href="/articles/duplicated-middle-cerebral-artery">MCA duplication</a>: reported incidence of ~1.5% (range 0.2-2.9%); parallels the main MCA and supplies the anterior temporal lobe</li>
+<a href="/articles/duplicated-middle-cerebral-artery">MCA duplication</a>: reported incidence of ~1.5% (range 0.2-2.9%); parallels the main MCA and supplies the anterior temporal lobe</li>

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