like moms since time immemorial, was constantly grousing at me about the habit. I am certain that Eve yelled at Cain and Abel about cracking their knuckles — at least when they weren’t busy fighting each other.

 

In her threats, my mother always said that if I kept cracking my knuckles, I’d get arthritis. Of course, being the ever-dutiful child that I was, I ignored her completely.

 

Let’s look first at what causes your knuckles to “crack.” On the Live Science website, Cory Binns wrote: “Inside a capsule that safeguards bones connected at a joint, synovial fluid keeps the cartilage, tissues, and muscles lubricated, and well nourished. Nutrients float inside the fluid, along with gases, such as oxygen, nitrogen, and carbon dioxide. As you bend your fingers, the joint capsule stretches. To make more room for the stretch, gases release out of the fluid. The pop of your knuckles is the sound of gas as it bubbles out of the fluid.”

 

You have to admit, making that popping noise is fun. But is there any harm? Turns out that mother was wrong about the arthritis. (She was also wrong on a few other bad habits, but that’s another story.)

 

As far as arthritis, the wiseGEEK website shoots it down summarily: “There is no proven connection between knuckle-cracking and arthritis, except for Dr. Mom’s lingering words of warning from childhood.”

In a Discovery Health article, Katherine Neer tells us that the only in-depth study made on knuckle-cracking was done by Raymond Brodeur and published in the Journal of Manipulative and Physiological Therapeutics. Brodeur examined 300 knuckle-crackers but found no apparent connection between joint-cracking and arthritis. However, the study showed that “habitual knuckle-poppers did show signs of other types of damage, including soft tissue damage to the joint capsule and a decrease in grip strength.” The possible damage is similar — although much less — to the damage a big league pitcher can experience in his shoulder and arm joints because of the repeated strain of his pitching motion.

So there is a chance for some damage, although minimal, from cracking your knuckles. The good news is that there’s evidence of increased mobility in joints right after popping. When the joints are manipulated, certain nerve endings are stimulated and the joints are relaxed.

One final, purely unscientific, observation: knuckle-cracking is heredity. Our two sons were constantly cracking their knuckles and I incessantly yelled at them about it. Of course, they ignored me. Then again, they ignored most everything else I said, too.

Sources: (Accessed , 2012)

• Discovery Health & Health, “What Makes Your Knuckles Pop”; 
• wiseGeek.com, “Is it Harmful to Crack My Knuckles?;
• About.com, “Does Cracking Your Knuckles Cause?;
• Live Science, “Why Knuckles Crack and Joints Creak”;