The big toe, not the thumb, is the most human digit
Thumbs get the credit for making us human, yet every primate has one, and ours is still partly primitive. The most evolved digit on the human body is the big toe. Its anatomy also explains why most of us cannot wiggle a single small toe on its own.
Each human foot normally carries five toes. The four smaller ones have three bones apiece, though in a minority of people the little toe lacks its middle bone; the big toe, the hallux, has only two. The classical Latin had several spellings for it, and today's hallux is a blend of them, a partner to pollex for the thumb. The Old English word tā may once have covered fingers as well, as many Indo-European languages use one term for both.
Control is shared. Apart from the big toe, the toes are moved mainly by two short muscles, one bending and one straightening, whose tendons attach along the sides of the bones and link the smaller toes together. That wiring is why independent movement of a middle toe is essentially impossible. The big toe and little toe each have their own dedicated muscles; the hallux is bent chiefly by a long flexor anchored deep in the back of the calf. Five separate nerves supply feeling to the skin of the toes.
Toe length is partly inherited. A dominant gene gives a second toe longer than the first, a trait called Morton's toe or Greek foot, while two copies of the recessive version produce the more common longer big toe. In walking, the toes supply balance, carry weight and push the body forward. Stubbing sprains the small joints; turf toe is a strain where toe meets foot.
The big toe attracts more than its share of trouble: it is the commonest site of ingrown nails, and the joint at its base is the usual target of gout attacks. Bunions deform that same joint, with a matching version on the little toe called a tailor's bunion. Toes can even stand in for fingers: surgeons transplant a second and third toe together to rebuild a hand that has lost several digits.
Source: Toe
