vessels in the back can take over so the Circle of Willis is important then how the blood vessels come together on the surf to the brain to help each other out is also important these are things that we don't have control over this is how you were born you're either born with a nice Circle of Willis or not and you're born with a nice collateral circulation it doesn't necessarily matter how old you are but how you were born so you can thank your parents for if you had good collaterals or not there's things that