This site is targeted at medical and radiology professionals, contains user contributed content, and material that may be confusing to a lay audience. Use of this site implies acceptance of our Terms of Use.

Anterior cerebral artery

The anterior cerebral artery along with the middle cerebral artery, forms at the termination of the internal carotid artery. It is the smaller of the two, and arches antro-medially to pass anterior to genu of the corpus callosum, dividing as it does so into its two major branches; pericallosal and callosomarginal arteries (see below). 

It supplies the medial aspect of the cerebral hemispheres back to the parietal lobe. 

Segments

The ACA is divided into three segments:

Branches

There are two main branching patterns of the ACA. In the first the A2 gives off the callosomarginal artery (which lies in the cingulate sulcus), and continues as the pericallosal artery. In this configuration the terminal (cortical) branches are given off the callosomarginal artery.

In the second configuration the callosomarginal is absent and the terminal branches arise directly from the pericallosal.

Terminal (cortical) branches

Orbital branches, 2 or 3 in number, branch over the orbital surface of the frontal lobe supplying:

  • olfactory cortex
  • gyrus rectus
  • medial orbital gyrus

They are named:

Frontal branches supply:

  • corpus callosum (with the exception of the splenium)
  • cingulate gyrus
  • medial frontal gyrus
  • paracentral lobule (as the branches reach over the vertex to supply a stip of cortex on the surface, they are responsible for supply to the lower limbs)

Parietal branches supply:

  • precuneus
Central branches

Multiple small branches given off proximally (A1, ACOM, proximal A2) supply:

The latter two (head of caudate and adjacent part of the internal capsule) are supplied by the recurrent artery of Heubner and associated smaller perforating branches. It has its origin near the A1-ACOM-A2 junction and can arise from all three, although usually it is from the A2. It curves back on itself and is at risk from ACOM aneurysm clipping.

Normal variants

  • ACA fenestration with a reported incidence of 0-4% of A1 segment fenestration 
  • azygos ACA: ACA territories supplied by a single A2 trunk; incidence of ~2% (range 0.2-4.0%) 
  • ACA trifurcation: three A2 segments; incidence of ~7.5% (range 2-13%) 
  • bihemispheric ACA: hypoplastic A2 segment with contralateral A2 segment dominance supplying both ACA territories; incidence of ~4.5% (range 2-7%) 
  • A1 segment absence/hypoplasia, contralateral A1 segment dominance and supply to ipsilateral A2 segment by a large anterior communicating artery; 10 % of individuals demonstrate hypoplasia of A1 segment using a diameter 1.5 mm or smaller
  • Asymmetry of A1 segment which is associated with ACA aneurysm
  • persistent primitive olfactory artery 6 

Related articles

Neuroanatomy

Updating… Please wait.
Loadinganimation

Alert_accept

Error Unable to process the form. Check for errors and try again.

Alert_accept Thank you for updating your details.