Your craniosacral system comprises the bones of the skull and the membrane system surrounding your brain and spinal cord (i.e., your central nervous system). It is named for the cranium ("cranio") and the sacrum ("sacral"), which is the triangle-shaped bone in your low back where the bottom of your spinal cord attaches.
 
When you think of the three major organs we need to live, you think of the heart, lungs, and brain, right? The heart has a natural, rhythmic motion we can feel when we take our pulse. The lungs also have a natural rhythm we can feel when we place our hands on our ribs and feel them expand and contract in synchrony with our breath.
 
So it makes sense that our body's other major organ -- the brain -- has a similar inherent rhythm. Of course it does. We call it the craniosacral rhythm. This soft, subtle motion is felt in the head in response to the production and reabsorbtion of the cerebrospinal fluid surrounding your brain and spinal cord. We also feel this rhythm bodywide via the connective tissue network (or fascia).
 
The craniosacral rhythm is often said to be reflective of the core essence of your being. It reflects your life force energy. Indeed, it can be a direct expression of your physical, mental, emotional, and even spiritual health. A strong rhythm may indicate a robust central nervous system that is able to oversee the function of all body systems easily. A shallower rhythm may indicate that the body is not able to function at its highest level of health or maintain homeostasis.

Within the body, motion is health. Everything vital to our existence -- organs, blood flow, the skeleton, etc. -- has a certain intrinsic motion much like the heart, lungs, and brain do. In order for the body to remain strong and healthy, all structures must maintain their natural movements. When things stop moving or movement is restricted, that's when pain or disease sets in. It's like the old adage, "Use it or lose it."