The 43-year-old singer took to Instagram to inform fans about her health scare, while sharing a picture of herself with her arm in a sling.
Without revealing any details about how she suffered the injuries, Mel thanked the doctors and nurses for their help, writing: "Thank you to all the wonderful nurses dr's and my amazing surgeon for the care and expertise given to me here at the hospital I've been staying at. Suffering two broken ribs, a severed right hand needing emergency care, to having had to have over a 3 hr surgery to repair the damage hence the purple sling.
"For now my right hand/arm is all stitched up and I'm trying to keep still to heal my broken ribs, ohhh the pain, but I'm in super safe hands with the care of everyone here at the hospital!!!!!"
Mel added she had been forced to cancel a New York signing for her new autobiography Brutally Honest, continuing: "I've had to unfortunately cancel my book signing today in NY, I apologise to each and everyone of you who bought their tickets to meet me today. I'm absolutely gutted but I can assure you it WILL happen at a later date. I promise."
She concluded her post by writing: "Thank you all for understanding, I love you all #accidentshappen #hospital #needtimetoheal."
Fans were quick to wish the Spice Girls star better, with one writing: "What happened mel? Next time you have to be 1000,000x careful. Love lots."
Prior to Mel's Instagram revelation, she had shared a Boomerang clip of herself on a night out on her social media, in which she showed off her sparkly rose gold outfit by spinning around.