The anterior communicating artery is a short vessel, about 4 mm long on average, that joins the left and right anterior cerebral arteries across the start of the deep groove between the hemispheres (the longitudinal fissure), in front of the optic chiasm. It is the front link of the circle of Willis. [1][2]
The 3D brain needs JavaScript. The text below still says where the anterior communicating artery is and what it does.
Opens with the blood-supply layer on (about 0.8 MB) and a top (axial) slice through the base of the brain, so the ring is seen from above: the lit link is the short bar across the front of it, between the two anterior cerebral arteries. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
Lit: the single anterior communicating artery, a short midline link at the front of the circle of Willis; the anterior cerebral arteries it joins are not lit (they have their own page). Every other artery shows in a darker colour. [3][1]
It crosses between the two anterior cerebral arteries at the start of the longitudinal fissure, the groove between the two hemispheres. [1]
Each anterior cerebral artery’s first part (A1) runs from the internal carotid to it; beyond it the artery continues as A2 up into the fissure. [4]
It lies in front of the optic chiasm and is the front link of the circle of Willis. [2][1]
Its form varies a lot: it can be duplicated, multiple, net-like (fenestrated) or very short, or missing with the two anterior cerebral arteries joined in one trunk; when it is large one internal carotid may feed both anterior cerebral arteries. [1][2]
What it does
It joins the left and right anterior cerebral arteries, so blood has a second route between the two sides of the front of the circle; normally almost no net blood flows through it. [1]
Together with the two posterior communicating arteries it gives the brain’s supply its alternative routes (collateral circulation). [5]
It gives off some of the small anteromedial central arteries, most of which come from the anterior cerebral artery; they enter through the anterior perforated substance and supply the optic chiasm, the front of the hypothalamus (including the supraoptic nucleus), the lamina terminalis and the front of the columns of the fornix. [1][6]
Other names
Latin: arteria communicans anterior; often shortened to ACoA or AComm. In the embryo the two anterior cerebral arteries grow toward each other and form it at the 21–24 mm stage. [1][4]
Size
On this model the anterior communicating artery fit in a box about 2 mm front to back, 7 mm side to side and 1 mm top to bottom (the box they fit in, not their volume). [3]
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.