Cyclist Mark Cavendish Suffers Broken Ribs, Collapsed Lung After Crash During Race

Mark Cavendish -- one of the greatest road sprinters of all time -- says he's in pain after a violent spill during an event in Belgium ... leaving him with 2 broken ribs and a collapsed lung.

The crash happened at the Six Days of Ghent competition Sunday night ... when the 36-year-old -- alongside his teammate -- collided with cyclist Lasse Norman Hansen.

You can see in the footage, a biker ahead of Cavendish and Hansen lost control ... causing them to crash into each other at full speed and go spinning on the track floor.

Cavendish stood up after the crash but was taken to the Ghent University Hospital for observation --- his team, Deceuninck-Quick-Step, announced Monday he broke 2 ribs on his left side and a small pneumothorax.

"It is expected that Mark will be discharged either later today or tomorrow morning," Cavendish's team said, "and will then undergo a period of recuperation."

Cavendish -- in his hospital bed -- thanked all the fans for showing love via IG -- saying, "Just want to say how overwhelmed & thankful I am for all the support and well-wishes."

"In a bit of pain, but a couple of nights with the incredible staff here at Ghent University Hospital should sort me out."

Cavendish -- who won 34 Tour de France stages -- was just named, by the Tours' director,  as one of the greatest sprinters in Tour history and cycling.