The middle cerebral artery (MCA) is one of the three major paired

cerebral arteries The cerebral arteries describe three main pairs of arteries and their branches, which perfuse the cerebrum of the brain. The three main arteries are the: * ''Anterior cerebral artery'' (ACA) * ''Middle cerebral artery'' (MCA) * ''Posterior cereb ...

that supply

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the c ...

to the

cerebrum The cerebrum, telencephalon or endbrain is the largest part of the brain containing the cerebral cortex (of the two cerebral hemispheres), as well as several subcortical structures, including the hippocampus, basal ganglia, and olfactory bulb. In ...

. The MCA arises from the

internal carotid artery The internal carotid artery (Latin: arteria carotis interna) is an artery in the neck which supplies the anterior circulation of the brain. In human anatomy, the internal and external carotids arise from the common carotid arteries, where these b ...

and continues into the

lateral sulcus In neuroanatomy, the lateral sulcus (also called Sylvian fissure, after Franciscus Sylvius, or lateral fissure) is one of the most prominent features of the human brain. The lateral sulcus is a deep fissure in each hemisphere that separates the ...

where it then branches and projects to many parts of the lateral

cerebral cortex The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of ...

. It also supplies blood to the anterior

temporal lobe The temporal lobe is one of the four Lobes of the brain, major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain. The temporal lobe ...

s and the insular cortices. The left and right MCAs rise from trifurcations of the

internal carotid arteries The internal carotid artery (Latin: arteria carotis interna) is an artery in the neck which supplies the anterior circulation of the brain. In human anatomy, the internal and external carotids arise from the common carotid arteries, where these b ...

and thus are connected to the

anterior cerebral arteries The anterior cerebral artery (ACA) is one of a pair of cerebral arteries that supplies oxygenated blood to most midline portions of the frontal lobes and superior medial parietal lobes of the brain. The two anterior cerebral arteries arise from t ...

and the

posterior communicating arteries In human anatomy, the left and right posterior communicating arteries are arteries at the base of the brain that form part of the circle of Willis The circle of Willis (also called Willis' circle, loop of Willis, cerebral arterial circle, and W ...

, which connect to the

posterior cerebral arteries The posterior cerebral artery (PCA) is one of a pair of cerebral arteries that supply oxygenated blood to the occipital lobe, part of the back of the human brain. The two arteries originate from the distal end of the basilar artery, where it bifur ...

. The MCAs are not considered a part of the

Circle of Willis The circle of Willis (also called Willis' circle, loop of Willis, cerebral arterial circle, and Willis polygon) is a circulatory anastomosis that supplies blood to the brain and surrounding structures in reptiles, birds and mammals, including huma ...

Structure

The middle cerebral artery divides into four segments, named by the region they supply as opposed to order of branching as the latter can be somewhat variable: *M1: The ''sphenoidal'' segment (stem), receiving its name due to its course along the adjacent

sphenoid bone The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of occipital bone, basilar part of the occipital bone. The sphenoid bone is one of the seven bones ...

. It is also referred to as the ''horizontal'' segment, though this may be misleading since the segment may descend, remain flat, or extend posteriorly the anterior (dorsad) in different individuals. The M1 segment perforates the brain with numerous '' anterolateral central'' (lateral lenticulostriate) arteries, which supply the

basal ganglia The basal ganglia (BG), or basal nuclei, are a group of subcortical nuclei, of varied origin, in the brains of vertebrates. In humans, and some primates, there are some differences, mainly in the division of the globus pallidus into an extern ...

. *M2: Extending anteriorly on the insula, this segment is known as the ''insular'' segment. It is also known as the ''Sylvian'' segment when the opercular segments are included. The MCA branches may bifurcate or sometimes trifurcate into trunks in this segment which then extend into branches that terminate towards the cortex. *M3: The ''opercular'' segments and extends laterally exteriorly from the insula towards the cortex. This segment is sometimes grouped as part of M2. *M4: These finer ''terminal'' or ''cortical'' segments irrigate the cortex. They begin at the external margins of the Sylvian fissure and extend distally away on the cortex of the brain. The M2 and M3 segments may each split into 2 or 3 main trunks (terminal branches) with an ''upper trunk'', ''lower trunk'' and occasionally a ''middle trunk''. Bifurcations and trifurcations occurs in 50% and 25% of the cases respectively. Other cases include duplication of the MCA at the

(ICA) or an accessory MCA (AccMCA) which arise not from the ICA but as a branch from the anterior cerebral artery. The ''middle trunk'' that exist in parts of the population, when present provides the ''pre-Rolandic'', ''Rolandic'', ''anterior parietal'', ''posterior parietal'' and the ''angular artery'' for irrigation instead of the ''upper'' and ''lower trunks''. The branches of the MCA can be described by the areas that they irrigate.

Frontal lobe

*''Lateral frontobasal'' (orbitiofrontal): This artery branches out anteriorly, superiorly and laterally to vascularize the inferior frontal gyrus. It "competes" in size with the ''frontal polar'' branch of the

anterior cerebral artery The anterior cerebral artery (ACA) is one of a pair of cerebral arteries that supplies oxygenated blood to most midline portions of the frontal lobes and superior medial parietal lobes of the brain. The two anterior cerebral arteries arise from t ...

*''Prefrontal arteries'': These arteries fan out over the insula and exit to the cortex via the medial surface of the frontal operculum. The arteries fan superiorly over the

pars triangularis The inferior frontal gyrus (IFG), (gyrus frontalis inferior), is the lowest positioned gyrus of the frontal gyri, of the frontal lobe, and is part of the prefrontal cortex. Its superior border is the inferior frontal sulcus (which divides it fro ...

and vascularize the inferior and middle frontal gyrus. Near the superior frontal gyrus these arteries

anastomose An anastomosis (, plural anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf veins, or streams. Such a connection may be normal ...

with branches from the ''pericallosal artery'' of the anterior cerebral artery. *''Pre-Rolandic artery'' (precentral): The artery extends out on the medial surface of the operculum and supplies the posterior parts of the middle and inferior frontal gyri as well as the lower parts of the pre-central gyrus. This artery branches once or twice and is relatively invariant across anatomies. *''Rolandic arteries'' (central): The artery extends out and exits from the central portion of the operculum then passes inside the central sulcus. This artery bifurcates in 72% of individuals and irrigates the posterior pre-central gyrus and the inferior portion of the post-central gyrus.

Parietal lobe

*''Anterior parietal'': This artery usually originates from a distal MCA branch. In some cases it branches from the rolandic artery or from the posterior parietal artery. It extends the length of interparietal sulcus and descends slightly posteriorly. *''Posterior parietal'': Emerges from the posterior end of the Sylvian fissure and extends first posteriorly, and then anteriorly along the posterior of the parietal lobe. It also branches to the supramarginal gyrus. *''Angular'': The angular artery is a significant terminal branch of the anterior or middle trunk of the MCA. It emerges from the Sylvian fissure and passes over the anterior transverse temporal gyrus and usually divides into two branches. One of the branches supplies the

angular gyrus The angular gyrus is a region of the brain lying mainly in the posteroinferior region of the parietal lobe, occupying the posterior part of the inferior parietal lobule. It represents the Brodmann area 39. Its significance is in transferring vis ...

while the other supplies the supramarginal gyrus, posterior superior temporal gyrus, and the parietooccipital arcus (sulcus). *''Temporooccipital'': The longest cortical artery, it runs posteriorly opposite to the center of the operculum. Upon its exit from the Sylvian fissure, it runs parallel to the superior temporal sulcus and supplies the superior and inferior occipital gyri. This vessel anastamoses with the posterior cerebral artery and may exist as one or two arteries, 67% or 33% of the time, respectively.

Temporal lobe

*''Temporopolar'': The artery extends from the sphenoidal segment of the MCA via the inferior surface of the operculum and supplies the polar and anterior lateral portions of the temporal lobe. The vessel can be identified in 52% of normal angiograms *''Anterior temporal'': This artery typically arises from the proximal MCA trunk and extends in the similar fashion as the ''temporopolar'' artery and vascularizes the same regions. *''Middle temporal'': This artery extends from the Sylvian fissure opposite to the inferior frontal gyrus and supplies superior and middle portions of the middle temporal lobe. It can be identified in 79% of angiograms. *''Posterior temporal'': This artery extends out and away from the operculum and turns in a step-wise manner first inferiorly then posteriorly into the superior temporal sulcus then to the middle temporal sulcus. This vessel supplies posterior portion of the temporal lobe and is the origin of several perforating arteries that irrigate the insula. It is readily identifiable in most radiograms.

Function

Areas supplied by the middle cerebral artery include: * The bulk of the lateral surface of the hemisphere; except for the superior inch of the frontal and

parietal lobe The parietal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus. The parietal lobe integrates sensory informa ...

(

), and the inferior part of the

. *Superior division supplies lateroinferior frontal lobe (location of

Broca's area Broca's area, or the Broca area (, also , ), is a region in the frontal lobe of the dominant Cerebral hemisphere, hemisphere, usually the left, of the Human brain, brain with functions linked to speech production. Language processing in the brai ...

i.e. language expression) *Inferior division supplies lateral temporal lobe (location of

Wernicke's area Wernicke's area (; ), also called Wernicke's speech area, is one of the two parts of the cerebral cortex that are linked to speech, the other being Broca's area. It is involved in the comprehension of written and spoken language, in contrast to B ...

i.e. language comprehension) *Deep branches supply the

as well as the

internal capsule The internal capsule is a white matter structure situated in the inferomedial part of each cerebral hemisphere of the brain. It carries information past the basal ganglia, separating the caudate nucleus and the thalamus from the putamen and the g ...

MCA occlusion site and resulting Aphasia *Global – trunk of MCA *Broca – anterior branch of MCA *Wernicke – posterior branch of MCA

Clinical significance

Occlusion

Occlusion Occlusion may refer to: Health and fitness * Occlusion (dentistry), the manner in which the upper and lower teeth come together when the mouth is closed * Occlusion miliaria, a skin condition * Occlusive dressing, an air- and water-tight trauma ...

of the middle cerebral artery results in Middle cerebral artery syndrome, potentially showing the following defects: #

Paralysis Paralysis (also known as plegia) is a loss of motor function in one or more muscles. Paralysis can also be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory damage. In the United States, roughly 1 in 50 ...

(-plegia) or weakness (-paresis) of the contralateral face and arm (faciobrachial) # Sensory loss of the contralateral face and arm. # Damage to the dominant hemisphere (usually the left hemisphere) results in aphasia (i.e.

or Wernicke's) # Damage to the non-dominant hemisphere (usually the right hemisphere) results in contralateral neglect syndrome, inaccurate localization in the half field, impaired ability to judge distance (nondominant parietal lobe). # Large MCA infarcts often have

déviation conjuguée Déviation conjuguée, also termed conjugate eye deviation (CED) or ipsilesional gaze shift, is a medical sign indicating brain damage (e.g. a stroke in the middle cerebral artery The middle cerebral artery (MCA) is one of the three major paire ...

, a gaze preference towards the side of the lesion, especially during the acute period. Contralateral

homonymous hemianopsia Hemianopsia, or hemianopia, is a visual field loss on the left or right side of the vertical midline. It can affect one eye but usually affects both eyes. Homonymous hemianopsia (or homonymous hemianopia) is hemianopic visual field loss on the sa ...

is often present.

References

External links

* * *
Blood supply at neuropat.dote.hu
{{Authority control Arteries of the head and neck