Well, now we know the physics behind knuckle-cracking

February 26, 2022, 07:20 AM

joel9507

Well, now we know the physics behind knuckle-cracking - WSJ

I always wondered about what made the sound when knuckles were cracked, and now technology has gotten to where they have figured it out...

quote:
People pull their finger away from the rest of their hand until there’s a deep, muffled click. When medical imaging finally improved to the point where it could spy on the inside of a finger during the process, the true culprit was revealed: a bubble.

quote:
X-rays and MRI scans show that at the moment of cracking, a gas-filled cavity pops into existence

non-paywalled link - "How Knuckles Get Cracking" - WSJ

Within the article was this bit of good news to finger-crackers everywhere:

quote:
there has been a persistent myth that regular joint-cracking can cause arthritis. This has been debunked, both by systematic scientific studies and by allergist Donald L. Unger.

February 26, 2022, 07:22 AM

Patriot

I always knew it was air…

Don’t know when I learned it, but this isn’t news.

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February 26, 2022, 07:24 AM

Balzé Halzé

Well, it's news to me.

Cool info.

February 26, 2022, 08:00 AM

Patriot

quote:
Originally posted by Balzé Halzé:
Well, it's news to me.

Cool info.

Well bully for you…

February 26, 2022, 08:02 AM

Patriot

https://en.wikipedia.org/wiki/Cracking_joints

February 26, 2022, 08:33 AM

Graniteguy

I am a joint cracking addict. Knuckles, wrist, knees, ankles, neck, scapula, etc. I can even crack my nose. (been broken 4x)

Drives my wife crazy.

February 26, 2022, 09:05 AM

Flash-LB

quote:
Originally posted by Patriot:
I always knew it was air…

Don’t know when I learned it, but this isn’t news.

Nope, I used to crack my knuckles back in the 60s and I read about why back then.

Must be a slow news day at the WSJ.

February 26, 2022, 10:09 AM

egregore

I like to say no knowledge is ever useless, but this comes close.

February 26, 2022, 10:11 AM

Lefty Sig

I crack my knuckles. And I have gas. Coincidence?

February 26, 2022, 10:16 AM

egregore

I have never felt the need to crack my knuckles, and probably couldn't if I tried. What triggers the impulse? Is the ability hereditary, like being able to roll your tongue into a U shape or cilantro tasting like soap?

February 26, 2022, 10:27 AM

PASig

I thought this had been known for years that it was gas, it’s the same reason your back cracks at the chiropractor.

February 26, 2022, 10:29 AM

P220 Smudge

In college, I was told it was this explanation given in the OP, but also the void either filling with nitrogen, or the sudden release or a nitrogen bubble.

February 26, 2022, 12:16 PM

Rey HRH

I'm with Patriot, I remember this being explained several decades ago.

I haven't had the need to crack my knuckles in a long time but I still occasionally crack my neck.

What I do miss though is being able to crack my spine by twisting side to side and bending backwards. I can't do that any more.

"It did not really matter what we expected from life, but rather what life expected from us. We needed to stop asking about the meaning of life, and instead to think of ourselves as those who were being questioned by life – daily and hourly. Our answer must consist not in talk and meditation, but in right action and in right conduct. Life ultimately means taking the responsibility to find the right answer to its problems and to fulfill the tasks which it constantly sets for each individual." Viktor Frankl, Man's Search for Meaning, 1946.