Why Knuckles Make a Popping Sound When Stretched

In a snappy Ted-Ed lesson written by Eleanor Nelsen and animated by Belfer Creative, narrator Addison Anderson explains exactly why knuckles and other joints release such as satisfying (or disgusting to some) popping sound when stretched. Cracking knuckles is simply the release of gas bubbles from joint cushioning synovial fluid, much in the same way gas bubbles are released when the cap is taken off a bottle of carbonated liquid.

Some people love the feeling of cracking their knuckles, while others cringe at the sound. But what causes that trademark pop? And is it dangerous?

via Geeks Are Sexy

Lori Dorn
Lori Dorn

Lori is a Laughing Squid Contributing Editor based in New York City who has been writing blog posts for over a decade. She also enjoys making jewelry, playing guitar, taking photos and mixing craft cocktails. Lori can be found posting on Threads and sharing photos on Instagram.