The Chiropractic adjustments has decidedly been associated with a popping sound or as some people call it a “crack”. It’s really not a crack; I can crack an egg, crack a whip, and occasionally crack a joke, but never have cracked a neck.
The popping sound that comes from any joint movement is gas escaping from the joints. Yes, you have gassy joints! Let me break it down. Around some of the body joints is a capsule. Within that capsule is fluid under pressure. Gas builds up in the fluid within the capsule. When the pressure is released the gas escapes, making that popping noise. It is similar to a soft drink can. There is gas under pressure and when you open the tab or lid the gas escapes and makes a distinctive sound. I hope this helps.