The garden sprinkler model of watershed rheology. Under normal conditions the borderzone (green) is nourished from both main vessels and is an area of luxuriant perfusion. Under conditions of diminished perfusion, in this case following cardiac arrest and subsequent pump dysfunction resulting in hypotension, the luxuriant zone becomes an area of diminished perfusion culminating in an area of infarction (red). I'm sure I've seen this presentation before but I do not remember the source.
