The extent of man from Vitruvius to Marfan.

It is frequently stated that patients with Marfan's syndrome have an arm span greater than height. This implies a characteristic different from the proportions in normal adult man, in whom span and height are often thought to be equal. Such equality of span and height, which allows man to be portrayed within a square, has been a widely held concept, immortalised by Leonardo da Vinci, that dates from the Roman Vitruvius. However, in the past two hundred years, anthropometry has shown that span exceeds height in 59-78% of normal adult white men. Thus not only is the classic concept of equality of span and height generally incorrect, but also a span greater than height cannot be considered characteristic of Marfan's syndrome. Paradoxically, in some affected individuals, Vitruvian equality of height and span may occur.