Peter Casaru, 59, posted on the social networking site that he was unable to move his legs.
He said he could not call for an ambulance from his remote cottage in Brecon, South Wales, because the battery in his
mobile phone was dead.
Mr Casaru said it took him over an hour to crawl to his laptop where he managed to post a message alerting his contacts to the emergency.
The father-of-one, who lives alone, wrote: "Can someone call 999? Ambulance for me.
"I need one now. I have fractured my back. Stuck to floor. No phone and glasses. Touch typing. Please help me."
Friends as far away as New York and Vancouver replied when they saw his updates and tried to call for help.
But it was his friend Juliet McFarlane, who lives six miles away, who was first to call 999 and two ambulances arrived at his house just 20 minutes later.
Mr Casaru, a photographer, said his doctors told him the spinal spasm he suffered could have killed him if he had not received emergency treatment.
He has had spinal problems since breaking his back in a quad bike accident six years ago.
He said: "That's the luck part of the whole story: that Facebook friends saved me."
The photographer thanked all the friends who had left messages and tried to help, adding: "I'm always joking when I go on Facebook, so I'm just glad they took me seriously."
