Dr. Donald Unger [pictured here], who was awarded the 2009 Ig Nobel Prize in medicine, is not the only scientist to study knuckle cracking. Consider, if you will:
“Consequences of Knuckle Cracking: A Report of Two Acute Injuries,” P.S. Chan, D.R. Steinberg, and D.J. Bozentka, American Journal of Orthopedics, vol. 28, no. 2, February 1999, pp. 113–4.[AIR 15:6] The authors, at University of Pennsylvania Medical Center, report:
“A question commonly asked of physicians focuses on the possible deleterious effects of knuckle cracking…. We present two cases in which acute injuries were suffered while the patients were attempting to crack their knuckles…. Our investigation shows that acute injuries can result from the forceful manipulation needed to achieve the audible pop of cracking knuckles and that patients should be counseled accordingly.”