College of Massage Therapists of British Columbia (CMTBC) Practice Exam

What is the Circle of Willis?

1. A junction of several important arteries in the abdomen

2. A junction of several important arteries at the top part of the brain

3. A junction of several important arteries at the bottom part of the brain

4. A junction of major veins in the heart

The correct answer is: A junction of several important arteries at the bottom part of the brain

The Circle of Willis is correctly identified as a junction of several important arteries at the top part of the brain. This crucial structure is located at the base of the brain and serves as a vital circulatory anastomosis. It allows for collateral blood flow between the anterior and posterior circulation of the brain, which can be especially important in cases where one of the main arteries supplying blood to the brain becomes occluded or narrowed. This circular arrangement of arteries includes contributions from the internal carotid arteries and the vertebral basilar system, ensuring a continuous supply of blood to various regions of the brain. In this way, the Circle of Willis enhances the brain’s resilience to ischemic events. Additionally, the functionality of this circle contributes to overall cerebral perfusion and helps maintain brain health. Any misunderstanding of the Circle of Willis is often due to its distinction from other vascular structures, such as those found in the abdomen or heart, which serve different roles in the circulatory system.