Detailed description of the anterior cerebral artery anomalies observed in a cadaver population.

Anomalies of the anterior cerebral artery (ACA) include the median ACA (MedACA), bihemispheric ACA (BihemACA) and the azygos ACA. Knowledge of these anomalies can be crucial to clinicians and neurosurgeons, especially during surgeries involving the interhemispheric region and in the interpretation of the clinical signs of a stroke. Since few reports exist on the origin, area supplied, diameter and length of the ACA anomalies, the aim of this study is to give a detailed description on the anatomy of the ACA anomalies. The ACAs of 60 brains were injected with a colored silicone. When an anomaly was observed, a detailed illustration of the course and pattern of the ACA and cortical branches were made. The origins and the areas supplied by the anomalous arteries were noted. The external diameter was measured using a digital micrometer and the length was measured using string and a ruler. There were seven cases (11.7%) of a MedACA and 12 cases (20.0%) of a BihemACA. The MedACA originated mostly from the anterior communicating artery, and from the A2 segment in one case. The MedACA was bilateral in four cases and unilateral in three cases. Excluding Cases 5 and 9, the BihemACA cases can be divided into two groups; one branch to the left hemisphere (n=3), and one branch to the right hemisphere (n=7). The average diameter of both the BihemACA and MedACA was 1.8mm. Studies rarely provide additional information on these anomalies. Therefore, the present study elaborated on the origin, diameter, length and the area supplied by these anomalies. The definitions are described in the literature, although additional criteria were still lacking and this was provided in the present study. Since information on these aspects of the ACA anomalies is scarce, future research should give detailed descriptions on the ACA anomalies.