Talk about Scary Spice – Mel B says she got sent straight to the hospital after an accident left her with a severed hand and broken ribs that required immediate surgery.

The Spice Girls member posted a photo of herself on the mend early Monday that featured her in a sling … and a gruesome (yet vague) description of what happened. Mel says she required emergency care in London this weekend after suffering 2 broken ribs, a "severed" right hand … and a heck of a lot of pain. It's unclear what caused this, but it sounds nasty.

Gary Madatyan, a close friend who has been in touch with Mel, tells TMZ, she was staying at a friend's house Saturday night. She was asleep in an upstairs bedroom when she woke up and decided to go downstairs. We're told the staircase was narrow and Mel lost her footing and fell.