Why do we crack our joints? Is it harmful? Maybe you’ve picked up this common habit yourself.
If not, most of us know folks who intentionally and constantly crack their knuckles (necks, backs, wrists, etc.), driving everyone around them batty.
Let’s get cracking on some answers …
Why do joints crack?
The longstanding biomedical question of what causes knuckle-cracking sounds was only recently solved!
The actual cause, scientists say: a phenomenon called tribonucleation, a “process where opposing surfaces resist separation until a critical point where they then separate rapidly creating sustained gas cavities.”
To sum it up: The separation between the bones produces the familiar cracking sound, not, as a previously popular theory suggested, gas bubbles bursting within the cavity that forms when the joints separate.
- See this brief video of what really happens when a knuckle cracks!
Grating, popping, or cracking sounds may also occur under a variety of circumstances, especially as we age:
- When deteriorating cartilage in knee, neck, or other arthritic joints exposes bone surfaces that rub and grate against each other
- When ligaments or tendons move over bone surfaces.
- When tight muscles, especially in the neck, release and allow joints to snap back to their usual position.
Most cracking/popping sounds are entirely benign. But see a doctor if you have pain or swelling in or around the affected joints, or if your joint locks up.
Why do people intentionally crack their knuckles (or other joints)?
Some folks say joint-cracking relieves tension, boredom, or pain, often emerging as a childhood coping behavior. But mostly, they say, it just feels good. So good that it becomes habitual to the point where many people have difficulty stopping. One commenter in an online forum for joint-crackers (no kidding!) identified himself as a recovering opioid addict who’d found that knuckle-cracking released the same burst of pleasure as a hit of heroin, albeit much briefer.
Does intentional cracking harm joints?
The consensus among medical experts is that joint-cracking does NOT cause arthritis and it does NOT cause any other harm, no matter how often or for how long you do it.
However, the clinical literature does contain a few reports of knuckle-cracking causing injury to ligaments or tendons, swelling in the joint capsule, or gradual weakening of the grip.
But even if habitual joint-cracking doesn’t injure your joints, it can annoy others to the point of straining relationships with family members, friends, and co-workers. If you can’t curb the practice at work, it can have negative effects, too.
Compulsive knuckle-crackers often lose awareness of their habit. If others keep mentioning that it bothers them, or if you have only recently become aware of how annoying your habit is to others, seek help from one of the many websites offering tips on breaking bad habits; ask for help from a close friend or family member; or consider getting help from a licensed therapist.
Now we know! What do you think of this? Know any knuckle-crackers? Or, are you one yourself?