Definition of Brain aneurysm

Brain aneurysm: A brain aneurysm is a small outpouching (an aneurysm) that looks like a berry and classically occurs at the point at which a cerebral artery departs from the circular artery (the circle of Willis) at the base of the brain. Berry aneurysms are prone to rupture and bleed. Also called a berry aneurysm.

An aneurysm is, by definition, a localized widening (dilatation) of an artery, vein, or the heart. At the area of an aneurysm, the wall is weakened, bulges and is at risk to rupture.

The word "aneurysm" comes from the Greek "aneurysma" meaning "a widening."