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In our feet, other than the large toe, the other toes cannot be moved separately. If we try to move them, then all the four toes move together. We cannot move each toe by itself.

Same thing occurs in the hands of some of us, where we cannot move the little finger by itself. While folding the little finger, the ring finger before that also has to be folded to some extent, and vice-versa.

An explanation to the problem with the ring finger and the little finger can be found here.

The phalanges make the toes. Are the phalanges of the small toes connected, such that we cannot move them separately?

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  • $\begingroup$ While I agree there are limitations to the phalanges you mention, I can easily move only my ring finger inwards towards my palm. I think there may be a more definitive way to describe the limitations on motion? $\endgroup$ – Sudachi Jan 30 '18 at 17:06
  • $\begingroup$ The answer here: biology.stackexchange.com/q/60075/107, effectively answers this as well. $\endgroup$ – kmm Jan 30 '18 at 17:31
  • $\begingroup$ Perhaps you should ask this question on the Music site, with special reference to pianists, harpists, and the like. Or someone like me, who's typing this comment with all 10 fingers. With fingers, it's basically a matter of training. I expect much the same would be true of toes. Searching for "toe dexterity" gets over 600K hits, including this: themovementfix.com/how-to-improve-your-toe-dexterity $\endgroup$ – jamesqf Jan 31 '18 at 2:59
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A relatively new area of the brain's cerebral cortex evolved to enable humans and other primates the necessary small motor skills to pick up small objects and deftly use tools, scientists now say. https://www.youtube.com/watch?v=zyl6eoU-3Rg

Primates can move their ears too, here's a theory of it. Other motor skills that are not often developed are individual eyebrow movement, pectoral flexing, ability to sneeze with your eyes open.

Hand movement is new and developing compared to chimps.

Toe movement is latent and receding.

The human hand is built up onto a squirrel/clawed paw, If you take a while to rotate your forearm and the flexors of the fingers, you will see that it's a mutated simple flexing mitt thing with with a new fine motor dexterity that you use all day, added on top of the vestigial clawing and grasping hand.

https://www.youtube.com/watch?v=vlwAoKpSI7s

This page says: Signals generated in the primary motor cortex travel down the corticospinal tract through the spinal white matter to synapse on interneurons and motor neurons in the spinal cords ventral horn. Ventral horn neurons in turn send their axons out through the ventral roots to innervate individual muscle fibers.

The motor cortex is subject to plasticity and remapping. To know this question is beyond my field of knowledge, someone else can go on from here :) you'd have to learn about the motor cortex, plasticity, vestigial nerves, nerve mappings, it's a fantastically complex topic.

What's interesting is the variety and quantity of different muscular abilities that are inherited by a population, it reflects an optimized level of evolutionary plasticity and specific types of variety of useful traits like muscle and joint proportions to ensure fast and flexible species development.

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  • $\begingroup$ plenty of humans can move their ears. $\endgroup$ – John Jan 30 '18 at 19:08
  • $\begingroup$ Other motor skills that are not often developed are individual eyebrow movement Interestingly, I can do this. $\endgroup$ – Wrichik Basu Jan 31 '18 at 5:46

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