There are two types of people in this world: those who crack their knuckles and those who shudder at the very thought.
While it might be a difficult habit to break - or crack, if you'll excuse the pun - a recent video showing what really happens when you crack your joints might be enough to put you off for life.
Ouch.
The video was taken under a fluoroscope, also known as an X-ray image intensifier, and uploaded to Imgur. The fascinating video has been viewed more than one million times (and counting).
The user, who is a student at a veterinary school, says a lecturer was teaching them how to use the device in a small hospital.
Reactions have been mixed.
A radiology student described the video as "satisfying", while another said: "As someone who cracks my knuckles and joints a lot, I don't think I will anymore."
Another commented: "I thought I was about to witness a finger breaking. That was intense!"
But despite the dramatic footage the researchers found no evidence that knuckle cracking causes immediate damage to the joints.
