What condition is characterized by a lack of blood flow to the brain due to a clot or breakage of a vessel?

The condition characterized by a lack of blood flow to the brain due to a clot or breakage of a vessel is a stroke. A stroke occurs when there is an interruption of blood supply to the brain, which can happen in two main ways: an ischemic stroke, caused by a clot that blocks blood flow, and a hemorrhagic stroke, resulting from the rupture of a blood vessel. Both types lead to the brain being deprived of oxygen and nutrients, resulting in potentially serious brain damage if not promptly treated.

In contrast, a concussion refers to a type of traumatic brain injury caused by a blow to the head, which can affect brain function but is not primarily about blood flow. Similarly, a contusion is a bruise on the brain resulting from trauma, which does involve some bleeding but is distinct from the vascular issues that define a stroke. An aneurysm is an abnormal bulge in a blood vessel that can lead to hemorrhagic stroke if it ruptures, but it does not itself denote the event of reduced blood flow to the brain that defines a stroke.