windgall
nounEtymology From wind + gall.
1
A puffy, typically fluid filled sac located just above the fetlock joint on a horse, generally appearing on old or poorly kept horses.
- It was a Bearn pony, from twelve to fourteen years old, yellow in his hide, without a hair in his tail, but not without windgalls on his legs […]1844, Alexandre Dumas (anon. translator), The Three Musketeers, Spark Publishing (2004) p. 12