Amateur jockey JT McNamara suffered a serious neck injury in a fall at the Cheltenham Festival.
Riding Galaxy Rock for Jonjo O'Neill in the Fulke Walwyn Kim Muir Challenge Cup the pair parted company at the first fence.
The 37-year-old, one of the leading amateurs on the circuit for a number of years, was airlifted to hospital after being treated by the on-course medics.
Conscious following the fall according to officials at the track, he was put in an induced coma before his transfer to Frenchay Hospital in Bristol.
Speaking at 9pm on Thursday Dr Adrian McGoldrick, chief medical officer for the Irish Turf Club, said: "JT has suffered a serious neck injury.
"He is being looked after at the regional spinal unit but as yet he is still waiting for a scan.
"So what we know so far is that he has a neck injury, but we will know far more in the morning when hopefully he will have had his scan."