We had a horrible experience recently with one of our pigs jumping from our arms. She was dragging her hind legs behind her and we were beside ourselves with grief and worry. We took her to the vet the next morning and he did an x-ray and found out that she hadn't broken anything and there was no deformation of the spine - both good things.
He also checked the reflexes of both feet with a sharp point and she had a decent reflex in one and a teeny-tiny bit in the other leg. He gave her a shot of cortisone and asked us to come back in three-four days.
In the meantime, she was eating and defecting and would move to get food or water, but always dragging her legs. It was awful to watch. When we took her back in three days, the vet gave another small shot of cortisone and said that he was cautiously optimistic about her chances of recovery.
After another three days, we noticed a bit of leg movement in one of the hind legs. Over the next four weeks, she improved a little bit every day. Now, after a month, she is about 95% back to normal on standing and running, even going up on her hind legs for hay at the top of the rack.
So, I just wanted to post for anyone else going through this kind of an experience that they can recover from a fall, although there is no guarantee and you can't really know how bad it is without a visit to the vet.