Definition: The word "arteriodiastasis" means "an abnormal condition where a single artery in the brain starts to widen, causing pain or discomfort." It's often associated with tumors that invade one of the primary arteries, such as the cerebral aorta (which carries blood from the head and neck to parts of the body) or the anterior cerebrovascular system. The term is also used in medical jargon to describe conditions where two or more arteries become narrowed together, sometimes due to an infection, stroke, or other problems.