UPFRONT | Roundup RESEARCH Alberta researchers offer insight on mystery of knuckle cracking In a study published re-cently, University of Alberta scientists describe how mod-ern imaging technology has shed new light on the age-old riddle of why some joints crack when you pull them. “It’s something that every culture, every society is inter-ested in,” said Dr. Greg Kaw-chuk, chiropractor and lead author of the paper published in the online journal Plos One. “We all do it. People love it or are repulsed by it.” But nobody had actually looked at how the noise beloved by annoying uncles is created. With the help of fellow chiropractor Dr. Jerome Fryer, Kawchuk decided to bring MRI technology to bear. No one had ever be-fore looked inside a knuckle as it cracked. “When we saw that, we said, ‘Wow! There’s a real opportunity here.’ It’s been sitting there waiting for some-one to do (it).” The team designed a care-fully calibrated knuckle-puller that resembles the kind of woven finger-trap on offer in novelty stores. The subject digit was placed under a mag-netic resonance imager and the requisite tug applied. Video of the event – which lasted about 310 milliseconds – was carefully analyzed. At first, the surface tension of the fluid in the joints kept the bones together. “As we increased the pull, suddenly you reach the point where you overcome that surface tension and the two joint surfaces suddenly fly apart,” said Kawchuk. “In that moment, we saw the creation of an air cavity that happens at the same time the sound is produced.” A similar effect can be created by pressing two hands together at the palm, then quickly separating them. The imager wasn’t able to determine what’s in the cavity, air or a gas released by sur-rounding tissues. Nor can Kawchuk be completely sure the cavity is what creates the sound. “We’re only imaging a very small slice of what’s happen-ing inside the joint. There’s things that are happening to the left and right and in be-tween our images that may be causing the sound, but we don’t see them.” The research does have real importance. Fingers aren’t the only joints in the body that crack. “By using this technique to look into people’s joints, we have a little bit of a window to better understand joint health.” -Bob Weber The Canadian Press BackSwing ‘15 June 23, 2015 – Bearspaw Country Club in Calgary www.cmcc.ca/ABBackSwing Sponsors: Bronze McLeod Law LLP Friend of CMCC Optimum Wellness Media Canadian Chiropractor CMCC’s golf tournament fundraiser Alberta September 9, 2015 – DiamondBack Golf Club in Richmond Hill www.cmcc.ca/BackSwing Sponsors: Silver Cofely Adelt GDF Suez Impact Cleaning Services Investment Guild ObusForme The Co-operators Group Insurance Bronze Allan M. Freedman, Ernie Wolkin, Footmaxx, RBC Wealth Management, Marsh Canada, NYRC, Paper Dimension Inc., Stagevision Inc., The Orthotic Group Canadian Memorial Chiropractic College Ontario Media Canadian Chiropractor www.canadianchiropractor.ca June 2015 Canadian Chiropractor 13
Chiropractic + Naturopathic Doctor June 2015: Page 13
