AKA miliary aneurysms 1). Occur primarily at the bifurcation of small (< 300 mcm) perforating branches of lateral lenticulostriate arteries in basal ganglia (found in 46% of hypertensive patients over age 66, but only in 7% of controls 2)). Possibly the origin of some “hypertensive” ganglionic (putaminal) hemorrhages, 3) but this is controversial.