I made a few sketches to explain pony leg/joint anatomy to somepony, but I figured other people might be able to use these sketches to learn pony anatomy as well.
For animal legs I've always remembered a picture from my biology book in high school which compared the skeleton structure in human arms with the legs/wings of animals. The "equivalent" bones had the same color, so it was really clear to see how the joints worked. (like this: [link])
These sketches are in no way anatomically accurate, they're just a simplified visualisation of the similarities between human and animal limbs and to show how you can use your arm as a reference when drawing ponies
Also, pony/horse bones don't look like that... I just drew some random bone-y thingies there x3
This is... well... I'm not going to say it's WRONG, as it isn't entirely inaccurate, plus we're talking about cartoon ponies here. However, there is a little discrepancy that I do feel should be pointed out. That discrepancy is exactly what parts of the legs correspond to what in the hind leg. First off, the knee joint is actually in the thigh of the cartoon ponies. What everyone assumes is the knee (and what you have listed here as corresponding to the elbow) actually corresponds to the ankle. It should be obvious by this point, but the only hinge joints past that in a human are the toes. Yes, the hooves are actually the toes of an equine, not the hands and feet. Like I said though, this diagram isn't entirely wrong, only slightly so. The forelegs are fine, but in the hind legs are missing a bone, the femur, which would be in-between the blue bone (tibia fibula) and the pelvis.
"These sketches are in no way anatomically accurate, they're just a simplified visualisation of the similarities between human and animal limbs and to show how you can use your arm as a reference when drawing ponies "