Emergency workers rushed to treat the victims in a chaotic scene of gore, screams and shattered glass, with the black Nissan ZX still inside the clinic.
"You just saw bones and blood all over," said Ana Rodriguez, a medical assistant at a clinic across the street.
Dr. Amani Eldessouky, who works across the street, said she saw a woman whose legs had been severed, another woman who lost one leg and a man bleeding profusely from the head. "It was a terrible scene. I wanted to start shaking," Eldessouky said.
Witnesses said the Nissan and a Lincoln Town Car were racing through a South Los Angeles business district when the Lincoln clipped the Nissan, sending it off course, police Lt. Paul Vernon said. The Lincoln drove off.
The driver of the Nissan, Ijumaa Owens, 33, of Los Angeles, was taken into custody and could face reckless driving charges, or vehicular manslaughter if anyone dies, Vernon said. The occupants of the Lincoln were wanted for hit-and-run, he added.
A deputy police chief initially said Owens appeared to be under the influence of alcohol or narcotics, but Vernon later said that did not appear to be the case.
Ten of the injured, including two children, were taken to five hospitals. Six victims were in critical condition, said Fire Department Assistant Chief Ralph Terrazas. Three others were treated and released.