This lack of stability is called Cranio-Spinal Instability(
CSI). In
CSI, the bones in the neck are able to move out
of their proper positions, tissues can sag down out of place, and spinal fluid flow may be impaired. The bone and tissue movement is often noticeable only when an individual with CSI is in an upright position and the bones and tissue return to their normal positions when the individual returns to a horizontal position. In severe cases, CSI may be accompanied by cranial settling.