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 viewed on an atomic and molecular scale as shown in this article. The estimated gross molecular contents of a typical 20-micrometre human cell is as follows: Body composition can also be expressed in terms of various types of material, such as: There are many species of bacteria and other microorganisms that live on or inside the healthy human body. In fact, 90% of the cells in (or on) a human body are microbes, by number (much less by mass or volume). Some of these symbionts are necessary for our health. Those that neither help nor harm humans are called commensal