According to the explanation of Dr. Tanvi Desai, D.C., offered from alphasciencecenter.com, the position of the spine is right behind jaw (particularly the mandible). When the spine is not parallel, will form the space between the vertebrae with JAWS, so that JAWS will move from its original position to create such spaces, along the jaw open. When we talk or chew, both jaw will allow the formed position of zig-zag, so that would make us not accidentally bite your tongue or the inside of the cheek.