MRI-scan of cracking Nuckles

<h3>What happens when you crack your nuckles?</h3>

Some say it is harmful, others say it isn’t. But what happens when you crack your knuckles? These scientists found out.

Cracking sounds emitted from human synovial joints have been attributed historically to the sudden collapse of a cavitation bubble formed as articular surfaces are separated. Unfortunately, bubble collapse as the source of joint cracking is inconsistent with many physical phenomena that define the joint cracking phenomenon. Here we present direct evidence from real-time magnetic resonance imaging that the mechanism of joint cracking is related to cavity formation rather than bubble collapse.

Source: http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0119470