brain aneurysm definition
A brain aneurysm (AN-yoo-riz-um) is a bulge or ballooning in a blood vessel in the brain. It often looks like a berry hanging on a stem.A brain aneurysm can leak or rupture, causing bleeding into the brain (hemorrhagic stroke).Most often a ruptured brain aneurysm occurs in the space between the brain and the thin tissues covering the brain.This type of hemorrhagic stroke is called a subarachnoid hemorrhage. A ruptured aneurysm quickly becomes life-threatening and requires prompt medical treatment. brain aneurysm (AN-yoo-riz-um) is a bulge or ballooning in a blood vessel in the brain. It often looks like a berry hanging on a stem.