Which arteries supply blood to the Circle of Willis?

The Circle of Willis is an important arterial structure located at the base of the brain that provides collateral blood flow between the anterior and posterior circulations. The correct answer, which involves the vertebral and carotid arteries, is accurate because these vessels are pivotal in forming the Circle of Willis.

The internal carotid arteries branch off from the common carotid arteries and enter the cranial cavity, contributing significantly to the anterior circulation of the brain. They give rise to the anterior cerebral arteries and the middle cerebral arteries, both of which nourish major regions of the cerebral hemispheres.

The vertebral arteries, which are part of the posterior circulation, arise from the subclavian arteries and ascend along the spine before entering the skull to form the basilar artery, which provides further supply to the posterior cerebral arteries. The basilar artery and the internal carotid arteries form the connections within the Circle of Willis, enabling a vital redundancy that ensures continuous blood flow to the brain even if one part of the vascular supply is compromised.

In contrast, the other answer options do not include the correct pair of arteries that supply the Circle of Willis. The carotid and radial arteries do not intersect at the Circle of Willis; instead, the radial artery is a peripheral vessel mainly serving the