指关节掰的咔咔响的声音来源让科学家们困惑了100多年。现在，《科学报告》的论文提供了解释（Now, a study in Scientific Reports at last provides an explanation）

科学家说，指关节掰的咔咔响的声音是一种特殊的破裂声音，是由手掌关节液中部分微小的空腔气泡破裂引起的。

与2015年加拿大科学家用产生气泡解释不同，他们的解释是气泡破裂。

2015年，加拿大阿尔伯塔大学的研究人员发表在《公共科学图书馆-综合》（PLOS ONE）上的研究证实“气体空腔说”——掰动手指，关节腔受到一定程度的拉力，此时关节腔内会形成腔隙，周围的气体在腔隙的作用下进入关节腔，连同液体一起迸发出清脆的响声。（掰指关节时的嘎吱响从何而来?）如果他们不发出爆裂声，他们怎么产生这种声音？

In 2015, however, an international team of researchers from Canada and Australia published a study in which they used magnetic resonance imaging to show that even after the crack, the bubbles in the joint persist. If they don’t pop, how do they make noise?

见：

Why Does Cracking Your Knuckles Make So Much Noise? Science Finally Has an Answer

hy Does Cracking Your Knuckles Make So Much Noise? Science Finally Has an Answer

Why Does Cracking Your Knuckles Make So Much Noise? Science ...

time.com/5220275/knuckles-crack-science-why-reason/

Cracked it! Experts find answer to the knuckle-popping puzzle

Cracked it! Experts find answer to the knuckle-popping puzzle ...

phys.org/news/2018-03-experts-knuckle-popping-puzzle.html

Here’s what makes that ‘popping’ noise when cracking knuckles

Here’s what makes that ‘popping’ noise when cracking knuckles

www.today.com/video/here-s-what-makes-that...