Jockey Luke Nolen is expected to remain in an Adelaide hospital for at least a week nursing injuries suffered in a fall at Morphettville.

Des O'Keeffe of the Australian Jockeys Association says Nolen will have an MRI scan on his back on Monday to double check there are no problems with his back.

Nolen, known internationally for his association with champion Black Caviar, came off in Saturday's Robert Sangster Stakes, just 40 minutes after he won the Group One Australasian Oaks on Abbey Marie.

It was his first top level win since he returned in February from a seven-month lay-off as he recovered from back surgery.

"Luke has a fractured collar bone and shoulder blade and fractured a couple of ribs," O'Keeffe told Melbourne radio station RSN.

"He has bruised his spleen and liver and has a minor issue with a lung.

"But his head and legs are fine."

O'Keeffe said although jockeys had mixed views on the compulsory safety vests, on this occasion it had done its job and protected Nolen from more serious injury.

Nolen fell when Miss Promiscuity appeared to stumble approaching the home turn and was hit as he lay on the ground by a horse which could not avoid him.