Three suspected joyriders were arrested at West Middlesex Hospital after an early morning car smash in Feltham.
The teenagers were driving a black Nissan Almera, which was involved in a head-on collision with a blue MGZS car, at 4.55am on February 26.
The driver of the second vehicle had to be cut free by firemen following the crash on the railway bridge, in Harlington Road East.
Watch manager Phil Watkins, of Feltham Fire Station, said: "The crash was quite hard and when we first arrived it looked much worse than it was. We had a lot of work to do, cutting someone free, but no one was badly hurt."
The driver of a third vehicle, which was clipped in the crash, was allowed to go home but the other two drivers and the two passengers of the Almera were all taken to West Mid, in Isleworth, by ambulance.
Suspecting the Almera may have been stolen, police accompanied the patients and arrested the 18 and 19-year-old passengers, who are both from Southall, on suspicion of taking the car without consent.
The 19-year-old driver, from Greenford, was arrested on similar charges and also on suspicion of dangerous driving. The trio were allowed to remain at the hospital to receive treatment but have been bailed to return to Southall Police Station on April 29.
Traffic was disrupted for several hours as officers gathered evidence at the scene.