pastern

vuohinen The area on a horse's leg between the fetlock joint and the hoof.
1918, Leo Tolstoy, Anna Karenina, translated by Louise and Aylmer Maude (Oxford 1998), page 158:

It was quite impossible to ride over the deeply-ploughed field; the earth bore only where there was still a little ice, in the thawed furrows the horse's legs sank in above its pasterns.

Below me, somewhere in the horse-lines, stood Cockbird, picketed to a peg in the ground by a rope which was already giving him a sore pastern.

(rfquotek)