Defending champion Chris Froome suffered fractures to his wrist and hand in the falls that forced him to pull out of this year's Tour de France.
Froome, 29, was injured in three falls over stages four and five.
"MRI scans done, confirmed fractures to the left wrist and right hand," the Team Sky rider said on Twitter.
Froome's withdrawal, and that of Mark Cavendish, means Geraint Thomas and Simon Yates are the only remaining Brits in the race.
After suffering the first of his falls just five kilometres into stage four, Froome was sent for an X-ray but was later given the all-clear to continue.
He fell twice more in wet conditions on the following day's stage before climbing into a Team Sky support car, unable to compete.
Team Sky lead doctor Alan Farrell explained that initial scans from the race doctor on stage four didn't confirm any fractures.
But he said further MRI scans showed a small fractured bone in Froome's left wrist and another in his right hand.
Farrell said: "The fact Chris hadn't felt discomfort in his right hand shows how tough he is, and the pain threshold he has.
"Chris has been incredibly brave throughout this whole process and clearly did not take the decision to withdraw from the Tour de France lightly."
In 2013, Froome became just the second Briton to win cycling's most prestigious race, one year on from performing a support role in Sir Bradley Wiggins' victory in 2012.
At the time of his withdrawal, Froome was seventh in the general classification, two seconds behind overall leader Vincenzo Nibali.
His absence leaves Italian Nibali, who continues to lead the race, and Spaniard Alberto Contador as favourites to claim yellow jersey victory, while Australian Richie Porte will lead Team Sky.
Farrell added that Froome is expected to return to training "in the next few weeks".