Teammates immediately stopped to provide assistance, as it quickly became obvious that the Swiss champion was not going to bounce up and resume the race.
Cancellara remained on the ground clutching at his collarbone as he received medical assistance before being taken away by ambulance. Television reports have broadcast that his collarbone was broken.
The crash changes the complexion of the race, as Cancellara started as favourite and has earned his reputation on the back of two consecutive podium finishes for the Tour of Flanders and the brutal Paris-Roubaix.
It didn’t finish there, either.
As the peloton traversed through a town at the 42nd kilometre, Green Edge lead rider Sebastian Langeveld clipped a spectator when he took to the footpath to try to gain places.
Such is the popularity of these one-day classics that it is expected that today's route will have more than a million spectators. It is perhaps inevitable that one of those spectators will try to occupy the same bit of space as a cyclist at some stage.
The collision dislodged Langeveld’s front wheel with predictable and sickening results. All indications are that he too suffered the quintessential cyclist's injury of a broken collarbone.
As the race heads toward its conclusion, it is Tom Boonen’s to lose with Cancellara gone.
Cycling is never that straightforward. This race didn’t become a one-day classic because it's predictable.
*After this was published, Tom Boonen (Omega Pharma-Quick Step) eclipsed Filippo Pozzato (Farnese Vini-Selle Italia) and Alessandro Ballan (BMC Racing) in a sprint to the line after the trio slipped away late in the race.
Boonen claimed his third victory at the Ronde van Vlaanderen, making him the fifth person to do so since the race began in 1913.