The popping sound is familiar to most of us. Knuckle, neck and back cracking seem to bring relief for some, but why? What is actually happening during the action? Here is a brief look at each of these noisy habits.

What happens when you crack your knuckles?

man wringing hands in painResearchers at the University of Alberta used magnetic resonance imaging (MRI) to understand the mechanics of knuckle cracking. Here is what they found:  a small pocket of gas (such as carbon dioxide and oxygen) forms and stays inside the joint area. “As the joint surfaces suddenly separate, there is no more fluid available to fill the increasing joint volume, so a cavity is created and that event is what’s associated with the sound,” said the lead researcher Gregory Kawchuk, of the University of Alberta. As reported by Nicky Phillips in the Sydney Herald, results of the study were published in the science journal PLOS One. Although the practice might be annoying to friends or family it is not generally thought to be harmful.

What happens when you crack your neck?

neckJust like with your knuckles, or any joint for that matter, the cracking sound is the movement of fluid and gases. Carbon dioxide, nitrogen, oxygen and fluids fill pockets between the joints and pressure on that fluid causes the familiar popping sound. ZocDoc offers this answer about what happens when you crack your neck. The noise you hear is the result of cavitation or the formation of air bubbles in the fluid between the joints. Doctors have more concern for neck cracking than they do for knuckle cracking. That is, in part, because of the delicate machinery involved. They want to be sure the spine is protected. If cracking your neck is a habit, pay attention to how you feel after the crack. If you notice any discomfort, stiffness or a catching sensation, it may be worth mentioning to your healthcare provider. An alternative to cracking for relief may be in order for you.

What happens when you crack your back?

In an interview for, Dr. Christopher Anselmi, a Chiropractor at Hospital for Special Surgery’s Integrative Care Center in New York City, advised against habitual back cracking. Although the practice is fine on occasion, Dr. Anselmi expressed concern about joint breakdown if cracking becomes excessive. If back pain or discomfort is a problem he suggests gentle stretching after a warm shower.

So the short answer for cracking your knuckles, neck and back is it is okay in moderation. If it becomes something you feel you need to do all the time because of stiffness and discomfort consider adding gentle stretches or yoga to your daily routine. If the problem persists, talk to your doctor.