The middle cerebral artery leaves the end of the internal carotid artery under the brain, runs sideways into the lateral (Sylvian) sulcus, crosses the insula and fans out over the outer face of the hemisphere. It supplies the bulk of that outer (lateral) surface, the insula and the front of the temporal lobe, and through small deep branches the basal ganglia and internal capsule. [1]
Lit: both middle cerebral arteries, left and right, with every branch the model draws — its first part, the insular part and the cortical branches (listed under “Inside it”). Every other artery shows in a darker colour. [2][1]
The 3D brain needs JavaScript. The text below still says where the middle cerebral artery is and what it does.
Slice
Opens with the blood-supply layer on (about 0.8 MB) and a top (axial) slice, so both middle cerebral arteries are seen running out sideways from under the brain into the lateral sulcus; turn it to watch the branches climb over the insula and fan across the outer face of each hemisphere. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
Each one arises from the internal carotid artery — which enters the skull through the carotid canal in the temporal bone — under the front of the brain, and continues into the lateral sulcus, the deep cleft between the frontal and temporal lobes. [1][3]
Its course is divided into four segments named for where they run: M1 (sphenoidal) runs sideways under the brain; M2 (insular) lies on the insula at the bottom of the lateral sulcus; M3 (opercular) runs outward from the insula towards the surface; M4 (cortical) are the fine end branches on the cortex. [1]
Its trunk most often splits in two (in about half of people) and less often in three (about a quarter): the upper division runs to the lower outer frontal lobe, the lower one to the outer temporal lobe. [1]
It is not one of the links of the circle of Willis: it leaves the internal carotid next to the ring, while the anterior cerebral artery, which also arises from the carotid, forms part of it. [4][1]
What it does
Overall it supplies the bulk of the lateral (outer) surface of the hemisphere, the front of the temporal lobe and the insula. [1]
Deep: the anterolateral central (lateral lenticulostriate) arteries leave its first (M1) part, pierce the underside of the brain and supply the basal ganglia and the internal capsule. [1]
Frontal lobe: its lateral frontobasal branch feeds the inferior frontal gyrus, its prefrontal branches the inferior and middle frontal gyri, and its pre-Rolandic (precentral) branch the back of the middle and inferior frontal gyri and the lower part of the precentral gyrus. [1]
Around the central sulcus: its Rolandic (central) branch runs inside the central sulcus and supplies the back of the precentral gyrus and the lower part of the postcentral gyrus. [1]
Parietal lobe: its parietal and angular branches supply the supramarginal gyrus, the angular gyrus and the back of the superior temporal gyrus. [1]
Temporal lobe: its polar and anterior temporal branches supply the pole and the front of the outer temporal lobe; the middle temporal branch its upper and middle parts; the posterior temporal branch its back, and gives small branches into the insula. The temporo-occipital branch reaches the outer occipital gyri. [1]
Inside it
The branches lit on each side, as the model names them: the sphenoid (M1) part with two anterolateral central (lenticulostriate) branches; the insular part; and the cortical branches — lateral frontobasal, prefrontal, artery of the precentral sulcus, artery of the central sulcus, anterior and posterior parietal, branch to the angular gyrus, polar temporal, anterior, middle and posterior temporal, and temporo-occipital. [2][1]
Other names
Often shortened to MCA (Latin: arteria cerebri media). Its four parts are named M1 to M4, from the carotid out to the cortex. [1]
Size
On this model the left and right middle cerebral arteries with their branches fit in a box about 171 mm front to back, 142 mm side to side and 103 mm top to bottom (the box they fit in, not their volume). [2]
Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); real brains vary in size and shape, so its measurements describe one model, not anyone’s brain.