Anatomical variations of circle of Willis - a cadaveric study
DOI:
https://doi.org/10.18203/2349-2902.isj20171016Keywords:
ACA, ACoA, CW, PCA, PCoA, Variations of circle of WillisAbstract
Background: The circle of Willis (CW) is a vascular network formed at the base of skull in the interpeduncular fossa. Its anterior part is formed by the anterior cerebral artery, from either side. Anterior communicating artery connects the right and left anterior cerebral arteries. Posteriorly, the basilar artery divides into right and left posterior cerebral arteries and each join to ipsilateral internal carotid artery through a posterior communicating artery. Anterior communicating artery and posterior communicating arteries are important component of circle of Willis, acts as collateral channel to stabilize blood flow. In the present study, anatomical variations in the circle of Willis were noted.
Methods: 75 apparently normal formalin fixed brain specimens were collected from human cadavers. 55 Normal anatomical pattern and 20 variations of circle of Willis were studied. The Circles of Willis arteries were then colored, photographed, numbered and the abnormalities, if any, were noted.
Results: Twenty variations were noted. The most common variation observed is in the anterior communicating artery followed by some other variations like the Posterior communicating arteries, Anterior cerebral artery and posterior cerebral artery (PCA) was found in 20 specimens.
Conclusions: Knowledge on of variations in the formation of Circle of Willis, all surgical interventions should be preceded by angiography. Awareness of these anatomical variations is important in the neurovascular procedures.
References
Moorehead KT, Moore SM, Chase JG, David T, Fink J. 1D and 3D models of auto- regulated cerebrovascular flow. J Biomech Eng. 2005;127:440-9.
William AN. Thomas Willis' understanding of cerebrovascular disorders. J Stroke Cerebrovasc Dis. 2003;12:280-4.
Ustun C. Dr. Thomas Willis' famous eponym: the circle of Willis. Turk J Med Sci. 2004;34:271-4.
Paul S, Mishra S. Variations of the anterior cerebral artery in human cadavers: a dissection study. J Anat Soc India. 2004;53:15-6.
Alpers BJ, Berry RG. Circle of Willis in cerebral vascular disorders. Arch Neurol. 1963;8:398-402.
Riggs HE, Rupp C. Variations in form of circle of Willis. Arch Neurol. 1963;8:8-14.
Fisher CM. The circle of Willis: anatomical variations. Vasc Dis. 1965;2:99-105.
Puchades-Orts A, Nombela-Gomez M, Ortuno-Pacheco G. Variations in form of circle of Willis: some anatomical and embryological considerations. Anat Rec. 1975;185:119-23.
Ashwini CS, Shubha R, Jayanthi KS. Comparative anatomy of the circle of Willis in man, cow, sheep, goat and pig.Neuroanatomy. 2008;7:54-65.
Tanaka H, Fujita N, Enoki T, Matsumoto K, Watanabe Y, Nakamura H. Relationship between variations in the circle of Willis and flow rates in internal carotid and basilar arteries determined by means of magnetic resonance imaging with semi-automated lumen segmentation: reference data from 125 healthy volunteer. Am J Neuroradiol. 2006;27:1770-5.
Sforza DM, Putman CM, Cebral JR. Hemodynamics of cerebral aneurysms. Annu Rev Fluid Mech. 2009;41:91-107.
Orlandini GE, Ruggiero C, Zecchi Orlandini S, Gulisano M. “Blood vessel size of circulus arteriosus cerebri (Circle of Willis): a statistical research on 1000 human subjects,” Acta Anatomica. 1985;123(1):72-6.
van Overbeeke JJ, Hillen B, Tulleken CAF. A comparative study of the circle of Willis in fetal an adult life. The configuration of the posterior bifurcation of the posterior communicating artery,” J Anatomy. 1991;176:45-54.
Stehbens WE. Aneurysms and anatomical variation of the cerebral arteries. Archives of Pathology. 1963;75:45-63.
Kim GE, Cho YP, Lim SM. The anatomy of the circle of Willis as predictive factor for intra-operative cerebral ischemia (shunt need) during carotid end arterectomy. Neurol Res. 2002;24:237-40.
Papantchev V, Hristov S, Todorova D, Naydenov E, Poloff A, Nikolov D, et al. Some variations of circle of Willis, important for cerebral protection in aortic surgery: a study in eastern Europeans. Eur J Cardiothorac Surg. 2007;31:982-9.
Tsutsumi M, Aikawa H, Onizuka M, Kodama T, Nii K, Matsubara S, et al. Neuroradiology 2008; 50:509-18. Windle BCA. On the arteries forming circle of willis. J.Anat and Phy. 1888;22:289.
Windle BCA. On the arteries forming circle of willis. J. Anat and Phy. 1888;22:289.
Fawcett E, Blachford JV. The circle of Willis. An examination of specimens. J Anat and Physiol. 1905;40:63-70.
Baptista AG. Studies on arteries of the brain. The anterior cerebral artery. Some anatomic features and their clinical implication. Neurology. 1963;13:825-35.
Nordon DG, Rodrigues Junior OF. Variations in the brain circulation – the circle of Willis. J. Morphol. Sci. 2012;29:4:243-7.
Morris PP. Cerebral vascular anatomy. Neuroimaging Clinics of North America. 1996;6:3:541-50.
Perlmutter D, Rhoton AL. Jr. Microsurgical anatomy of the anterior cerebral artery- anterior communicating artery- recurrent artery complex. JNeurosurg. 1976;45(3):259-72.
Puchades-Orts A, Nombela-Gomez M, Ortuno- Pacheco G. Variation in form of circle of Willis: Some anatomical and embryological considerations. Ana- tomical Record. 1975;185:119-24.
Rhoton Jr AL. The supratentorial arteries. Neu- rosurgery. 2002;51:53-120.
Padget DH. The development of the cranial ar- teries in the human embryo. Contribution to embryology. Carnegie Institution. 2008;32:205-61.
Kapoor K, Singh B, Dewan I. Variations in the configuration of the circle of Willis. Anatomical Science International. 2008;83:96-106.
Jain PN, Kumar V, Thomas RJ, Longia GS. Anomalies of Human Cerebral Arterial Circle. J.Anat.Soc.India. 1990;39(2):137-46.
Vare AM, Bansal PC. Arterial pattern at the base of the human brain. J Anatomical Society of India. 1970;19(3):71-9.
Blackburn IWN. Anomalies of the Encephalic Arteries among the Insane. Journ. Comp. Neurol. and Psych. 1907;17:493-517.
Von Mitterwallner F. Varyationsstatische Untersuchungen a den basalen Hirngefassen. Acta Anat. 1955;24:51-8.
Stopford JSB. Arteries of the pons and medulla oblongata. J Anatomy and Physiology. 1916;50:131-64.
Berk ME. Some anomalies of the circle of Willis. British Journal of Anatomy. 1961;34:221-6.
Carpenter MB, Noback CR, Moss ML. The anterior choroidal artery; its origin, course, distribution, and variations. Arch Neural Psychiatry. 1954;17:714-22.
Takahashi S, Suga T, Kawata Y. Anterior Choroidal Artery: Angiographic Analysis of Variations and Anomalies. AJNR. 1990;11:719-29.
Malamateniou C, Adams ME, Srinivasan L, Allsop JM, Counsell SJ, Cowan FM, et al. The anatomic variations of the circle of Willis in preterm-at-term and term-born infants: An MR angiography study at3T. AJNR Am J Neuroradiol. 2009;30:1955-62.
Macchi C, Catini C, Federico C, Gulisano M, Pacini P, Cecchi F, et al. Magnetic resonance angiographic evaluation of circulus arteriosus cerebri (circle of Willis): A morphologic study in 100 human healthy subjects. Ital J Anat Embryol. 1996;101:115-23.
Voljevica A, Kulenović A, Kapur E, Vucković I. Angiography analysis ofvariations of the posterior segment of the circle of willis. Bosn J Basic Med Sci. 2005;5:30-4.
Poudel PP, Bhattarai C. Anomalous formation of the circulus arteriosus and its clinico-anatomical significance. Nepal Med Coll J. 2010;12:72-5.
De Silva KR, Silva R, Gunasekera WS, Jayesekera RW. Prevalence oftypical circle of Willis and the variation in the anterior communicating artery: A study of a Sri Lankan population. Ann Indian Acad Neurol. 2009;12:157-61.
Eftekhar B, Dadmehr M, Ansari S, Ghodsi M, Nazparvar B, Ketabchi E.Are the distributions of variations of circle of Willis different in different populations?-Results of an anatomical study and review of literature. BMC Neurol. 2006;6:22.
