Playboy and Instagram sensation Katie May took a nasty fall during a photo shoot last week, injuring her neck, and that is the leading candidate for what caused her fatal stroke ... TMZ has learned.
Sources with direct knowledge of Katie's situation tell us the accident happened late last week when she was shooting in Los Angeles. We're told Katie's neck pain after the fall was so bad, she went to a hospital to get checked out, and was released later that day.
But on Friday the pain remained -- she tweeted, "Pinched a nerve in my neck on a photoshoot and got adjusted this morning. It really hurts!"
Our sources say the operating theory is the 34-year-old model did not pinch a nerve, but instead tore the carotid artery in her neck. As we first reported, doctors told Katie's family the tear caused a blood clot which broke off and caused her stroke on Monday. It's called a carotid artery dissection.