The ACA is classified into 5 segments with the smaller branches from the ACA “callosal” arteries (supracallosal) considered as the A4 and A5 segments 1).
A2 (vertical): from ACOM to the origin of the callosomarginal artery
The segment of the anterior cerebral artery distal to the anterior communicating artery (A2 to A5) has also been called the pericallosal artery. The two first conical branches of the ACerA supplying the medial surface, the orbitofrontal and the frontopolar arteries, usually arise from the A2 segment. The segments A3 to A5 give rise to other cortical branches to supply the medial surface of the hemisphere.
The paracentral artery frequently stems from the A4 segment.
The A5 segment gives rise to the superior and inferior parietal arteries. All the cortical branches arise more frequently from the pericallosal than from the callosomarginal artery.
1. Recurrent artery of Heubner: 80% arise from Al (one of the larger medial lenticulostriates, remainder of lentic-ulostriates may arise from this artery head of caudate, putamen, and an-terior internal capsule
A. internal frontal branches 1. anterior 2. middle 3. posterior
It supplies the frontal lobes, the parts of the brain that control logical thought, personality, and voluntary movement, especially of the legs.
Certain aspects of the anterior cerebral artery (ACA) cortical branches tend to vary, including absent or additional arteries, variation in origin, and changes to diameter and length. Knowledge of these factors can be crucial in aneurysm and arteriovenous malformation surgery. Few studies report on these aspects and a South African study have not been completed. Therefore, the aim of this study is to report absent or additional arteries, the origin, diameter and length of ACA cortical branches in a Western Cape population.
A coloured silicone was injected into the ACA of 121 hemispheres (60 right, 61 left), consisting of 83 males and 38 females. Specimens were divided in groups younger than 34 (n=36), between 35 and 48 (n=35), older than 49 (n=40), and unknown (n=10). There were three population groups; coloured (n=72), black (n=37), white (n=10), and unknown (n=2). Any absent or additional arteries were noted, as well as the origins. External diameter and lengths were measured using a digital micrometre, string and a ruler.
The diameter and lengths indicated significant differences between right and left, sex, age and population groups. Most commonly absent (callosomarginal artery) and additional (paracentral lobule artery) arteries were noted. Origins were similar to the literature; however, previously unreported origins and common trunks were also observed.
The aspects reported have been neglected in previous work and neurosurgeons should be aware of these variations and anomalies to avoid complications. Studies should continue to assess the cerebral vasculature since undocumented variations are still being reported 2).