This is my first ever message, so I hope that I am following the correct etiquette. Internationally 'vasodilatation' is the accepted description. I suspect that the American contraction to vasodilation is mistakenly used due to ignorance compounded by common usage? A similar event is occurring with 'disorientate', it is being described as 'disorient'. The Orient, is a region. So it makes no sense to 'dis' a region. Clearfell (talk) 03:57, 17 April 2011 (UTC)