Cracking your knuckles does not hurt your bones, the sound you hear is just gas bubbles bursting.
The “pop” of a cracked knuckle is caused by bubbles bursting in the synovial fluid — the fluid that helps lubricate joints. The bubbles pop when you pull the bones apart, either by stretching the fingers or bending them backward, creating negative pressure. … Chronic knuckle-cracking may lead to reduced grip strength.
Knuckle “cracking” has not been shown to be harmful or beneficial. More specifically, knuckle cracking does not cause arthritis. Joint “cracking” can result from a negative pressure pulling nitrogen gas temporarily into the joint, such as when knuckles are “cracked.” This is not harmful.
What is arthritis?
Arthritis is an inflammation of the joints. It can affect one joint or multiple joints. There are more than 100 different types of arthritis, with different causes and treatment methods. Two of the most common types are osteoarthritis (OA) and rheumatoidarthritis (RA).