(Adds Jacob injury)
By Justin Palmer
CHELTENHAM, England, March 14 (Reuters) - Jockey Ruby Walsh, the all-time leading rider at the Cheltenham Festival, suffered a fractured right arm after a heavy fall in the opening race on Gold Cup day on Friday.
The Irishman was catapulted to the turf from the pacesetting Abbyssial at the second flight in the Triumph Hurdle. He was taken to hospital after sustaining a compound fracture to his right humerus, officials at the racecourse said.
Walsh, who has ridden 41 winners at the Cheltenham Festival, including three this year, is now set to miss next month's Grand National meeting at Aintree.
There was more drama before the start of the Albert Bartlett Novice Hurdle when Daryl Jacob suffered a broken knee.
Jacob's mount, Port Melon, appeared to be spooked near to an enclosure packed with racegoers. He tried to jump over a plastic running rail and deposited the jockey into an area of hard concrete.
Jacob, successful on Lac Fontana in the preceding County Hurdle, received lengthy attention, delaying the start of the third race by some 12 minutes.
"He's broken his knee and will be operated on tomorrow," said trainer Paul Nicholls.
"It's not great news. The incident looked horrific.
"He's ridden a winner and is generally in good spirits despite having a terrible injury like that."
(Reporting by Justin Palmer, editing by Pritha Sarkar and Stephen Wood)