Vitruvian Man

This image exemplifies the blend of art and science during the Renaissance and provides the perfect example of Leonardo's keen interest in proportion. In addition, this picture represents a cornerstone of Leonardo's attempts to relate man to nature. Encyclopedia Britannica online states, "Leonardo envisaged the great picture chart of the human body he had produced through his anatomical drawings and Vitruvian Man as a cosmografia del minor mondo (cosmography of the microcosm). He believed the workings of the human body to be an analogy for the workings of the universe." It is also believed by some that Leonardo symbolized the material existence by the square and spiritual existence by the circle. Thus he attempted to depict the correlation between these two aspects of human existence. According to Leonardo's notes in the accompanying text, written in mirror writing, it was made as a study of the proportions of the (male) human body as described in Vitruvius, who wrote that in the human body:
-a palm is the width of four fingers
-a foot is the width of four palms (and is 12 inch)
-a cubit is the width of six palms
-a man's height is four cubits (and thus 24 palms)
-a pace is four cubits
-the length of a man's outspread arms is equal to his height
-the distance from the hairline to the bottom of the chin is one-tenth of a man's height
-the distance from the top of the head to the bottom of the chin is one-eighth of a man's height
-the maximum width of the shoulders is a quarter of a man's height
-the distance from the elbow to the tip of the hand is one-fifth of a man's height
-the distance from the elbow to the armpit is one-eighth of a man's height
-the length of the hand is one-tenth of a man's height
-the distance from the bottom of the chin to the nose is one-third of the length of the head
-the distance from the hairline to the eyebrows is one-third of the length of the face
-the length of the ear is one-third of the length of the face

The navel is naturally placed in the centre of the human body, and, if in a man lying with his face upward, and his hands and feet extended, from his navel as the centre, a circle be described, it will touch his fingers and toes. It is not alone by a circle, that the human body is thus circumscribed, as may be seen by placing it within a square. For measuring from the feet to the crown of the head, and then across the arms fully extended, we find the latter measure equal to the former; so that lines at right angles to each other, enclosing the figure, will form a square.

Vitruvius goes through some trouble to give a precise mathematical definition of what he means by saying that the navel is the center of the body, but other definitions lead to different results; for example, the center of mass of the human body depends on the position of the limbs, and in a standing posture is typically about 10 cm lower than the navel, near the top of the hip bones.

The previous text can be found on Wikipedia when a search is made for "Vitruvian Man" and "Vitruvius". Marcus Vitruvius made most of these initial observations and mathematical relations during his lifetime as a Roman citizen around the 1st century BC. Leonardo da Vinci lived in the 15th century AD and further investigated the same ratios and they can be seen in applications in his works of art. I urge everyone who actually read to this point in the blog to consider what they've just taken in. I, for example, think it is interesting that the navel is the center of the body, but when the arms are held down the center of gravity is at the hips. This is applicable in many sports where it is crucial to gain advantage by getting lower and pushing an opponent away from a point, but to also gain advantage at other times by rising above them using the full potential of outstretched limbs. Please post any other observations and whether or not you found this an informative and worthwhile read in comments on this blog.