Whats the cracking sound??

One of the most common questions my patients ask me is “What is the cracking sound during an adjustment?” or “Is something breaking??”

This sound is known as a Cavitation or an audible release. It is caused by the opening of the joint surfaces which takes place during an adjustment. Each joint contains a liquid called synovial fluid which reduces friction between the joint surfaces. When the joint surfaces are opened, the pressure in the joint capsule is lowered which allows for an expansion of gas bubbles in the synovial fluid. These bubbles persist for approximately 30 minutes before the gas is absorbed back into solution.

Diagram of gas expansion during an adjustment