Jerry McGrath was taken to hospital for X-rays after an incident in Lingfield's final race.
The jockey was riding Vegas Blue in division two of the Watch Off The Fence On attheraces.com 'Jumpers' Bumper' NH Flat Race when she fell on the home turn.
McGrath was bringing the evens favourite with her run, but the Nicky Henderson-trained mare became short of room and clipped the heels of another horse.
The daughter of Getaway brought down Jordan Nailor's mount Perfect Percy, who was under pressure at the time and 150-1 outsider Lord Howard, ridden by Alexander Thorne.
All three riders were attended to by the on-course medical team.
McGrath was taken to hospital where he will be checked over.
The horses were reported to be unhurt following the two-mile contest, won by Lucky's Dream (6-4) and Tom Scudamore.
A stewards' enquiry which will look into what happened was adjourned to a later date.
Lingfield's clerk of the course George Hill said: "Jerry McGrath is going to hospital for further examination.
"He was treated on the track by paramedics.
"The other two jockeys were OK."
Earlier in the afternoon, Strong Economy came from an unpromising position to take the Retraining Of Racehorses Handicap Chase (1.55) at Ayr.
Derek Fox's mount traded at odds of 879-1 in-running before winning by a length-and-three-quarters.
