What is a brain aneurysm and what causes a brain aneurysm?
The brain gets its blood supply from arteries known as the Circle of Willis. It is located at the base of the brain and is a loop of arteries that join in a circle then send branches out to all parts of the brain. These arteries deliver nutrition (glucose and oxygen) to the brain cells. The junctions where these arteries come together can form weak spots. These weak spots can balloon out and fill with blood, creating the outpouchings of blood vessels known as aneurysms. These sac-like areas may leak or rupture spilling blood into surrounding tissues. While the prevailing thought has been that aneurysms are congenital (meaning that people are born with them), it is now thought that they are due to microscopic damage to the artery walls caused by abnormal flow at the junction points where the arteries come together. There are other rare causes of aneurysms. Mycotic aneurysms are cause by infections of the artery wall. Tumors and trauma can also cause aneurysms to form. Drug abuse, especi
