A brain (cerebral) aneurysm is a bulging, weak area in the wall of
an artery that supplies blood to the brain. In some cases, a brain aneurysm may
cause no symptoms and go unnoticed. In other cases, the brain aneurysm
ruptures. This releases blood into the skull and causes a stroke.
When a brain aneurysm ruptures, the result is called a subarachnoid
hemorrhage. Depending on the severity of the hemorrhage, brain damage or death
The most common location for brain aneurysms is in the network of
blood vessels at the base of the brain called the circle of Willis.