Cracking knuckles and other joints


‘Cracking’ or ‘Popping’ Your Knuckles, Neck and Other Joints – Is It Harmful?

“Cracking” or “popping” your knuckles, neck, ankles or back can bring some brief relief after long bouts at sitting at the computer. Generally, cracking or popping the body’s joints are not necessarily harmful habits — as long as you don’t overdo it or as long as it does not produce pain or discomfort. For some people, these noises happen naturally during normal daily activities -- maybe after waking up in the morning or standing up and walking away from your workstation. But why do the body’s joints pop? And when it is a good idea to see a doctor?

Charles M. Lawrie, M.D., a board-certified, fellowship-trained orthopedic surgeon with Baptist Health Orthopedic Care.


The cracking sound you hear from popping joints comes from tendons or muscles moving over the joint, or from the popping of nitrogen bubbles normally found in the joint space.
A person can’t crack the same knuckle or joint twice right away because it takes some time for the gas bubbles to accumulate again in the joint.

In the short-term, cracking joints likely won’t do any damage. For example, rarely would “cracking the neck” damage vital nerves, ligaments and bones. But caution is warranted over time, explains Charles M. Lawrie, M.D., a board-certified, fellowship-trained orthopedic surgeon with Baptist Health Orthopedic Care.

“Depending on the cause, popping or cracking your joints may or may not be harmful. However, to be on the safe side, is probably best to avoid intentionally causing joint popping, cracking or snapping as over time some of the causes may lead to joint damage.”

Painful joint popping can be a symptom of arthritis, tendinitis (inflammation of a tendon), or bursitis, which is caused by inflammation of the bursa, a small, fluid-filled sac that helps lubricate the body’s joints.

What is actually making that sound when you crack or pop a joint? 

“There is no clear consensus as to why our joints pop,” said Dr. Lawrie. “The leading theory as to why our joints pop is called cavitation. Most of the joints in our bodies are enclosed in capsules, thickened structures that act like water balloons, holding in the joint fluid that helps nourish and lubricate the joint.

What exactly is cavitation? It’s when “external forces are put on the joint fluid liquid, causing small bubbles to form within the joint fluid, that then pop, resulting in the popping and cracking sounds,” he adds. “This may be the cause of the ‘pop’ that people feel when they crack their knuckles.”

Sounds made by joints, especially in individuals with arthritis, can stem from other causes.

“Other sounds made by joints may be related to damage or irregularity in the joint surface or internal structure of the joint,” said Dr. Lawrie. “When these irregularities rub against each other, it results in a crack or grind. These noises are commonly felt by patients with arthritis.”

In some cases, patients may be able to “actually partially dislocate their joints, leading to a snap or pop when the joint returns to its normal location,” he said. “Outside of the joint, ligaments or tendons may snap over parts of bones or joints quickly, resulting in a snapping sensation as well.”

Are there symptoms from joint popping that should prompt you to see a doctor?

“Joint noises that are accompanied by pain deserve the attention of an orthopedic physician,” said Dr. Lawrie. “Joint noises that are accompanied by a sensation of a joint dislocating also should be evaluated further. Simple knuckle cracking usually does not need to be investigated.”

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With internationally renowned centers of excellence, 12 hospitals, more than 27,000 employees, 4,000 physicians and 200 outpatient centers, urgent care facilities and physician practices spanning across Miami-Dade, Monroe, Broward and Palm Beach counties, Baptist Health is an anchor institution of the South Florida communities we serve.

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