Como - Belgium's Jan Bakelants suffered fractured ribs and vertebrae in a shocking crash during Saturday's Giro di Lombardia.
Millions of television viewers watched images of another Belgian, Laurens De Plus, go over his handlebars and off the edge of the road into a deep ravine during Saturday's one-day classic in northern Italy.
But three other riders also crashed on the same perilous descent, with 31-year-old Bakelants being the worst affected.
The AG2R rider suffered seven fractures to the ribs and broke two vertebrae in a fall in the same place as De Plus, whose Quick-Step team said he had escaped without serious injury.
Bakelants was forced to apologise after gaining a measure of notoriety in June when he made derogatory remarks about podium girls in a newspaper interview ahead of the Tour de France.
Italian Simoine Petilli also came out of it with several injuries, suffering a broken collarbone and shoulder blade, and fractures to his neck and one vertebrae, as well as concussion and a cut to his forehead.
His team UAE Emirates said he remained in hospital overnight.
Colombian Daniel Martinez was the fourth rider to crash on the same descent but escaped any fractures and like De Plus was quickly released from hospital.