Under the external hoof, horses have 5 digits
No, They don't..
"The horses foot contacts the ground only with the hoof of the third digit [like our middle toe] in an almost vertical position [like a ballet dancer, en pointe]," says Gheorghe M. Constantinescu, professor of veterinary anatomy, University of Missouri-Columbia and author of the book Clinical Dissection Guide for Large Animals.
Only splint bones alongside the cannon bone remain of its second and fourth toes. [P.D. Garrett, DVD, MS]
Moreover, the so-called cannon bone is much longer proportionately than ours.
What do I mean by "cannon bone"? Look at your foot.
The five bones going from your ankle to your toes correspond to the one bone in the horses foot: the cannon bone.
But, its huge running half way up the horses leg to what looks like its knee but is actually its ankle (called the hock).
Almost all trace of its other toes has vanished. Only splint bones alongside the cannon bone remain of its second and fourth toes. Short, strong ligaments tie the splint bones to the cannon bone.