estalos

Estalos refers to the cracking or popping sound commonly associated with the manipulation of joints, particularly the fingers, toes, knees, and spine. This sound, often described as a snap or crack, is produced by the rapid formation and collapse of gas bubbles within the synovial fluid that lubricates these joints.

The scientific term for this phenomenon is cavitation. When a joint is stretched or moved in a way that increases the volume of the joint capsule, the pressure of the synovial fluid decreases. This drop in pressure allows dissolved gases, primarily nitrogen and carbon dioxide, to come out of solution and form bubbles. The rapid expansion and subsequent collapse of these bubbles is what generates the audible estalo.

While the sound of estalos can be startling or even perceived as unpleasant by some, research generally indicates that cracking one's own joints does not cause arthritis or long-term damage. The practice is largely considered harmless, although excessive or forceful manipulation could potentially lead to minor soft tissue injury in rare cases. Some individuals find the act of cracking their knuckles to be a relieving sensation, possibly due to the release of tension in the joint. The opposite action, preventing bubble formation, would require maintaining consistent pressure, which is not typically how the sound is produced.