Ruffian - the highest rated US filly of the 20th century. Right up there with, and possibly ahead of, Zenyatta & Rachel Alexandra.
In July 1975 she was 10 from 10 when racing a match with that year's Kentucky Derby winner Foolish Pleasure. Then this happened.
Quote:
“As Ruffian left the starting gate, she hit her shoulder hard before straightening herself. The first quarter-mile (402 m) was run 221⁄5 seconds, with Ruffian ahead by a nose. Little more than 1 furlong (201 m) later, Ruffian was in front by half a length when both sesamoid bones in her right foreleg snapped. Vasquez tried to pull her up, but the filly wouldn't stop. She went on running, pulverizing her sesamoids, ripping the skin of her fetlock and tearing her ligaments until her hoof was flopping uselessly. Vasquez said it was impossible for him to stop her. She still tried to run and finish the race.”
Surgery was carried out but failed and there was no option but to euthanise.