Willie Shoemaker, who enjoyed a relatively injury-free career as the winningest jockey in horse racing history, now faces partial paralysis after an auto accident.

Shoemaker "suffered severe injuries, the most critical of which is paralysis of his extremities associated with a fracture and dislocation of his neck," Shoemaker's wife, Cindy, said in a statement Tuesday.It was not immediately known whether the former rider is in jeopardy of permanent paralysis.

The 59-year-old jockey-turned-trainer was alone Monday when the four-wheel drive vehicle he was driving overturned and tumbled down a 50-foot embankment near suburban San Dimas, about 30 miles from downtown Los Angeles.

Shoemaker was arrested on suspicion of drunken driving. Results of a blood-alcohol test won't be available for about two weeks, the Highway Patrol said.

Shoemaker was listed in serious condition at Centinela Hospital Medical Center, known for its expertise in sports medicine and orthopedic surgery.

"Every jockey's greatest fear is being in a spill and being permanently paralyzed," said Dan Smith, who co-wrote Shoemaker's 1975 autobiography, "The Shoe." "Shoe led a charmed life in that regard. He only had two serious injuries."

Shoemaker rode in 40,350 races. His last serious track accident was in 1969, when he suffered a broken pelvis and ruptured spleen.

The 4-foot-11 Shoemaker weighed 98 pounds while he was riding. When he was born in 1931, he was given little chance of survival, Smith said.