Does anyone know why you hear a cracking sensation on the base of the skull, shoulder or behind the neck when we stretch? I almsot hear this all the time I do it. Does it have anything to do with posture?
There are a few possible causes for the crack you hear. One is the carbon dioxide within the joint, another is a ligament that flips over the bone when you move, another reason is that a bone may be out of alignment and when you move your neck, it pops back into place.
If you're concerned, talk to your doctor and see a chiropractor (try and find one that uses an instrument called a hammer, not manual manipulation)
The popping sound you hear, kinda like when you crack your knuckles, is carbon dioxide built up in the cartilage between the bones. It cracks and pops after you've been in the same opsition for awhile. It won't hurt you to do so, either, and most of the time it makes you feel better.