Morphological Variations of Circle of Willis: A Human Cadaveric Study

What is it about?

Morphological Variations of Circle of Willis: A Human Cadaveric Study

Featured Image

Photo by Victor Freitas on Unsplash

Photo by Victor Freitas on Unsplash

Why is it important?

Background & Objectives: The Circle of Willis is a large arterial anastomosis in the base of the brain between carotid and vertebrobasilar system. There is considerable individual variation in the pattern and caliber of these vessels. Aim is to study the configuration of CW and its variations. Materials and Methods: This study was carried out in 50 brain specimens obtained from embalmed human cadavers. The CW was studied in detail in each specimen with reference to its formation and variations. Results: In this study, completeness of the CW was noted in 45 (90%) brai n specimens out of 50. The circle was found to be incomplete in 5 (10%) out of 50 specimens. Anterior part of the circle was incomplete in 4 brains (8%), whereas the posterior part of the circle was found deficient in 1 specimen (2%). Symmetry was seen in 27 (54%) of the 45 circles, the circle was found asymmetrical in 18 specimens (36%). Asymmetry was due to abnormal anterior part in 7 specimens (14%) and abnormal posterior part in 11 specimens (22%). Fetal PCA was found in 9 specimens (18%). PCoA was absent in 1 (2%), hypoplastic in 1 specimen (2%). Single median ACA was noted in 2 brains (4%). A1 was missing in 1 specimen (2%). ACoA was missing in 4 specimens (8%), double ACoA was observed in 2 circles (4%) and was plexiform in 1 brain (2%). Interpretation & Conclusion: Complete symmetrical CW was seen in 27 specimens (54%). The circle was incomplete in 5 specimens (10%), most frequently in the anterior part of the circle accounting for 8%. The circle was anomalous in 18 brains (36%), observed most frequently in the posterior part of the circle accounting for 22%. Variations noted were absence, hypoplasia and duplication of the vessels forming CW.

Perspectives