Which vessels are involved in forming the circle of Willis?

The circle of Willis is a crucial anatomical feature in the brain that provides collateral circulation, ensuring blood flow even if one part of the circulation is compromised. The formation of the circle of Willis involves several key arteries.

The correct response includes the anterior communicating artery (ACOM), the anterior cerebral artery (ACA), the internal carotid artery (ICA), the posterior communicating artery (PCOM), the posterior cerebral artery (PCA), and the terminal branches of the basilar artery. Each of these vessels contributes to the unique configuration of the circle of Willis.

• The anterior communicating artery connects the two anterior cerebral arteries and aids in equalizing blood flow between them.

• The internal carotid arteries supply blood to the anterior circulation, dividing into the ACA and the middle cerebral artery (MCA).

• The posterior communicating arteries bridge the internal carotid artery and the posterior cerebral arteries, allowing for potential collateral flow from the anterior circulation to the posterior circulation.

• The posterior cerebral arteries, derived from the basilar artery, complete the posterior part of the circle.

This comprehensive involvement of all these arteries is what makes option D the correct choice, as they together form the complete structure of the circle of Willis. Understanding the function and anatomy of these vessels is essential for compreh