Bilateral Absence Of Posterior Communicating Arteries - A Case Report.pdf

The major arterial supply to the brain is provided by the circle of Willis, an arterial circle situated in the interpeduncular cistern of the brain. It is formed by the anastomosis of the branches arising from the internal carotid and vertebral arteries. The posterior communicating artery is the main anastomotic channel between the carotid and vertebrobasilar circulation. During a routine dissection of a 70-year-old male cadaver, bilateral absence of posterior communicating arteries was observed, with the right vertebral artery being smaller than the left. Individuals with absence of posterior communicating artery or vertebral artery hypoplasia are more prone to develop stroke, migraine, and cognitive dysfunction. The knowledge of variation in the posterior communicating arteries is crucial for diagnosing neurological disorders and is also important from a surgical and angiographic point of view.

The posterior communicating artery arises from the posterolateral wall of the cerebral part of the internal carotid artery and runs posteromedially to enter the interpeduncular fossa, where it joins the posterior cerebral artery. It gives off 2-10 posteromedial central branches that supply the optic chiasma, optic tract, mammillary body, hypothalamus, thalamus, and posterior perforating substance. Variations in the pattern and caliber of the arteries that form the circle of Willis are common, with complete circle of Willis found in 60% of cases, and incomplete circle of Willis mostly due to absence of posterior communicating arteries.

In a case report, bilateral absence of posterior communicating arteries was observed in a male cadaver, with the right vertebral artery being smaller than the left. There was hemorrhage in the right cerebral hemisphere, and the internal carotid artery terminated by dividing into anterior cerebral and middle cerebral arteries. The two anterior cerebral arteries were connected to each other by the anterior communicating artery, and the basilar artery terminated at the upper border of the pons by dividing into right and left posterior cerebral arteries.

Variations in the origin, termination, and distribution of the arteries at the base of the brain are common, and in most cases, the brain function may not be affected due to collateral circulation and compensation from the arteries of the other side. However, individuals with absence of posterior communicating artery or vertebral artery hypoplasia are more prone to develop stroke, migraine, and cognitive dysfunction. The presence of posterior communicating arteries and anterior communicating artery is crucial for effective collateral circulation through the circle of Willis.

References:

[1] S. A. Gunnal, M. S. Farooqui, and R. N.Wabale. Anatomical Variations of the Circulus Arteriosus in Cadaveric Human Brains. Neurology Research International Volume 2014, Article ID 687281, 16 pages.

[2] Crossman AR. Vascular supply of the brain. In Standring S, Gray’s Anatomy: The Anatomical Basis of Clinical Practice. 40th international edition. Edinburg: Elsevier Churchill Livingstone; 2008. P. 247- 252.

[3] Kapoor K, Singh B, Dewan LI. Variations in the configuration of the circle of Willis.