The 17-time Paralympic gold medallist was due to defend her time trial title in Canada but scans showed she suffered more damage than it had initially appeared after a crash at a World Cup race last Sunday.
Storey wrote on Instagram: “Apologies for the radio silence since my crash last Sunday, I’ve been limiting screen time to manage the concussion symptoms I suffered and the strategy was working well.
“I had a plan to rest and recuperate, follow head injury protocol with regards to building up my riding time, and hopefully enable myself to start the Road Time Trial this morning.
“Unfortunately it wasn’t just the concussion that needed attention and, whilst initial rib pain was manageable with paracetamol, that changed late on Wednesday night when suddenly I couldn’t breathe properly.
“A chest X-ray at the local Emergency Room confirmed at least two broken ribs but then a subsequent ultrasound to check for punctured lung was inconclusive.
“Yesterday a CT scan showed the fracture sites were very inflamed and irritated but thankfully showed my left lung in tact. I wasn’t entirely in the clear though as, due to the fracture pain and inability to breathe deeply, I have a partially collapsed lung.
“I’m devastated I won’t be on the start line this morning, it’s always an honour to try and defend a title but sadly that can’t happen given my injuries.”