Length of foot as a function of length of ulna.

[Guest mba2005]

I want to post this interesting relationship because I want to find out how many people actually realize that the human body has ratios.

 

Does anyone knows the linear function that describes the relationship between lenght of the foot and lenght of the ulna?

[Sayonara]

Google for anthropometric ratios.

[coquina]

I learned a lot of them when I took art in order to draw figures in proportion. Your hand is as long as your face. You are 7 heads tall, your elbow is at your waist, your mouth extends to the pupils of your eyes - your ears are level with your eyes (convenient, else how would we hang glasses on our face?).

[Sorcerer]

Heh, most humans are in proportion like that. Ones that aren't are ugly, sad but true.

[Ophiolite]

Beyond the fact of the ratios, is the why of the ratios. I doubt that many are trivial, though some will be coincidental.

 

One suspects that many of the relationships depend upon efficient application of power to the limbs, and thus to strengths of materials - in this case bone and muscle.

 

From a quick scan of a score or so of the links turned up by Sayonara's suggested google, then such ratios are being used extensively to identify abnormalities and to predict final growth proportions.

 

What in particular, mba2005, drew you to the foot-ulna combination?

 

 

Hypothtetical conversation overheard in faculty lounge:

A: "His body seems out of proportion in some way."

B: "He has a very low torso:tibia+femur ratio. It's makes it easier for him to put his foot in his mouth."

[coquina]

I think some athletes - especially runners, have femurs that are longer than usual. When I was in high school, there was one girl in gym who outran the rest of us. She was very tall. One day we were all on the floor preparing to do situps - everyone's head was lined up evenly across the mat. I remember noticing that her waist and hips were in about the same place as every one else's, but that her thighs were several inches longer.

 

Since then, I have tried to check out that proportion with regard to olympic athletes, it seems that many of them have disproportionately long thighs. It would certainly help them have a longer stride.

 

I think it is true of some of the very tall basket ball players too.

[Jake712]

Im not sure if this is what your looking for, but:

 

For all those who have read The Da Vinci Code by Dan Brown, or perhaps you saw it somewhere else, you will know that the name for the ratio which the human body seems to follow is called Phi. I don't remember any of the other body parts that follows it, but I'm pretty sure that the femur-shin (tibia/fibula) and humerous-ulna/radius have a 1.6180339887... to 1 ratio in length. Seems possible that this may apply to other body parts as well.

However, i do not know any specific linear function for those two parts.