The 75-year-old woman remains in hospital in a critical condition.
The incident occurred on A461 Lichfield Road, Shelfield, Walsall at just before 1pm.
Steve Parry, a West Midlands Ambulance Service spokesman, said: "Ambulance crews arrived to find a pedestrian had been in collision with a car on the Lichfield Road.
"A woman in her seventies was found to be unconscious and she was treated for serious head and multiple limb injuries at the scene.
"The patient was anesthetised by an air ambulance doctor before being immobilised with the use of a neck collar and placed on a spinal board.
"She was conveyed by air ambulance to the Queen Elizabeth Hospital further assessment and treatment.
"The hospital was alerted to the serious condition of the patient.
"The driver of the car was uninjured."
The road remained closed for four hours following the crash, and the driver of the car spoke to officers at the scene.
Anyone who witnessed the crash between the black Vauxhall Vectra and the pedestrian should call the police on 101.
No arrests have been made.