What’s that sound?

One signal feature of chiropractic adjustments is the “crack” that often accompanies the manipulation. The cause of the noise has recently been investigated by a team lead by Greg Kawchuk, DC, of the University of Alberta, Canada. “Real Time Visualization of Joint Cavitation” was published on April 15, 2015 in PLOS One and available in full text here. The researchers performed real-time MRI images of an interphalangeal joint of a finger and found a “rapid cavity inception at the time of joint separation and sound production after which the resulting cavity remained visible.”