Protruding sac in the wall of a vein, artery, or heart, frequently caused by microbial infection; may present as pain, pressure on nearby organs, or cardiac weakening.

An aneurysm is an outward bulging, likened to a bubble or balloon, caused by a localized, abnormal, weak spot on a blood vessel wall. Aneurysms may be a result of a hereditary condition or an acquired disease...