What is that popping/cracking sound?
Picture a suction cup on a window. Now when the suction cup is quickly pulled off the window, a popping sound is heard. A vacuum is created, and the air rushes in to fill this vacuum. Something similar can happen in your body when the adjustment occurs: a small vacuum is created in the space between the bones in your back, the vertebrae, resulting in a temporary influx of synovial fluid, or the dissolved gasses in the synovial fluid. The fluid or the gas rushes into the vacuum that we just created between the bones, causing the sound.
