Body proportions a series of continuous geometric progressions. Polykleitos uses the distal phalanx of the little finger as the basic module for determining the proportions of the human body, scaling this length up repeatedly by to obtain the ideal size of the other phalanges, the hand, forearm, and upper arm in turn. Leonardo da Vinci believed that the ideal human proportions were determined by the harmonious proportions that he believed governed the universe, such that the ideal man would fit cleanly into a circle as depicted in his famed drawing of "Vitruvian man". Body proportions While there is significant variation in anatomical
Composition of the human body Not all elements which are found in the human body in trace quantities play a role in life. Some of these elements are thought to be simple bystander contaminants without function (examples: caesium, titanium), while many others are thought to be active toxics, depending on amount (cadmium, mercury, radioactives). The possible utility and toxicity of a few elements at levels normally found in the body (aluminium) is debated. Functions have been proposed for trace amounts of cadmium and lead, although these are almost certainly toxic in amounts very much larger than normally found in the body. There is evidence that