Charcot - Bouchard aneurysms: lt results from weakening of the wall of cerebral artery, by lipohyalinosis (deposition of lipids and hyaline material) caused by hypertension. Hypertensive hemorrhage shows a predilection for the distribution of the lenticulostriate arteries (branch of middle cerebral artery) with small (lacunar) hemorrhage, or large hemorrhages obliterating the corpus striatum. Including the putamen and internal capsule. Hypertensive hemorrhages also commonly occurs in cerebellum and pons amd are often fatal.
Berry aneurysms (small saccular aneurysms) are the result of congenital defects in the media of blood vessels and are located at the bifurcations of arteries.
Atherosclerotic aneurysms are fusiform (spindle-shaped) aneurysms usually located in the major cerebral vessels. They rarely rupture, but may become thrombosed
Mycotic (septic) aneurysms result from septic emboli, most commonly from subacute bacterial endocarditis.