Feet. Some may find them pretty, or even alluring. Not me. Whilst hands are true marvels of what evolution can achieve, our feet are very far removed from being such. Their ad-hoc nature is all too apparent.
Humans are plantigrade, as are many tree-dwelling creatures and only a few land-dwellers (like bears). That means our heels touch the ground and not only the tips of the fingers. Most land dwellers are digitigrade, that is they walk on their fingers or their tips. That has the advantage of allowing for greater speed – and indeed even humans resort to moving on their toes when speed is the priority.
Professor Kos emphasised that although “plantigrade” means “touching the ground with the whole sole” this is not in fact true. Our feet do not touch the ground with the whole sole , not as such. There are only three points that bear weight – the heel, the big joint at the base of the big toe and the joint at the base of the fourth toe. That is why we are able to stand on one foot – it still provides three points of contact for stability.
And just as it is with the hand, most of the muscles that actually move the feet are not in the feet, but on the calf.
kestrel says
Wow, that is super interesting. I never thought about being able to stand on one foot before but I can see you are right.
I’ve done drawings like this for a horse foot, and they are really really different. Now you point out they are walking on their fingertips, it makes so much sense!
Ice Swimmer says
The three points of load-bearing contact, two on the ball of the foot* and one on the heel is interesting indeed.
I wonder how it is with plantigrades that move on all fours like bears? Do they also have multiple points of contact per foot. Bears leave tracks that are much like those of flat-footed humans, AFAIK.
Also, Wikipedia claims that rats are plantigrades. I wonder, to what degree they actually are.
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* = I had to check Wikipedia to see what they are called in English. Ball of the foot is päkiä in Finnish and heel of the foot (but not a shoe) is kantapää (literally base head, head is pää).
rq says
Also, ankles are a clear argument against intelligent design. C’mon, ask me how I know! (Evolution, you really suck.)
In any event, I am enjoying this series and learning quite a bit. In uni I only did some osteology, I’m fascinated by the muscles and connecting tissue and your stories. It’s all so intricate (and beautifully drawn!). Perhaps too intricate (see: ankles)…
rq says
Incidentally, Ice Swimmer, the Latvian word for the back of the head is pakausis (pa- being a prefix signifying ‘under’ (pasaule, the word for ‘world’, meaning literally ‘beneath the sun’ or ‘undersun’ and padebeši an alternate term for clouds -- the ‘undersky’) and kausis or kauss associated with the skull, also kauss means goblet, like for wine… that really ran away from me) being , which means the same as kantapää. The heel of the head? I like that.