Microsurgical Anatomy of Circle of Willis in Korean Cadavaric Specimen

ABSTRACT

The authors studied and analyzed microscopically the structure, length and diameter of each part of Willis circle in 264 cerebral hemispheres of 182 autopsied patients in the Taegu area from 1984 to 1990. The mean length of each A1 was 14.1mm and diameter at distal A1 was 2.25mm. The most common anatomical anomaly of the ACA part was A1 that of hypoplasia which appeared in 7.5% of the cases. The origin of the Heuner a. was accounted for the highest incidence of AcoA(82.5%). The length of AcoA. Noted 3.5mm with the incidence of duplication and triplication in 38.6%. The inner diameter of ICA noted 3.9mm at the communicating segment in ICA, and the average length of C4 was 12.5m. Except 5 hemispheres of undetectable origin at ICA, all the anterior choroidal a. originated from ICA, and the double stump of which noted 15.5%. Fetal type PcoA. Showed 6.6% of all and average length of the a. was 13.5mm. The inner diameter of MCA was 3.1mm and the mean length of M1 noted 15.5mm. The length of each P1 noted 6.95mm and the inner diameter of basilar a. at 1cm below the bifurcation was 3.3mm. The mean circumference of willis circle including both side of A1, P1, PcoA. AcoA. And choroidal and communicating segment of ICA was 88.6mm. Incidental finding of unruptured aneurysm noted 5.3% and junctional dilatation of PcoA. Showed 11.4% of all the cases.