Fascia encases all elements of the human body. Every muscle, every muscle fiber, every organ, the brain, the eyes has it's protective fascial wrapping.
All these wrappings are themselves contained in a larger wrapping the superficial fascial layer just under the skin. This completely continuous webbing, from the little toe all the way into the brain, connects, as well as separates and protects, all functional units of the body. The fascial webbing shares this property of being completely continuous and covering the last millimeter of the human body only with two other systems, the circulatory and the nervous system. Neither bones nor muscles offer that type of continuity.
Fascia is often confused with muscle. Muscles and muscle fibers are enclosed within the fascia, just as the pulp of the orange is contained within its separating cellular walls. Just as it is possible to extract the juice and pulp of an orange and still have a shell that retains its shape, it would be possible (in theory at least) to remove the 'muscular pulp' in a body from its fascial envelope, leaving its external form relatively intact. Muscle is a highly contractile and highly responsive unit, fascia is less so - as a protective layer, it must be more stable.
Using a model we could say that the structure of a human body is made up of a myofascial webbing draped around bony elements, much like a three-dimensional piece of clothing. Since the skeletal structure is not continuous, it is up to the organization of that webbing and the intelligence of muscles adjusting the tensions within it, to determine the position of the bones, the functioning of joints and even to a certain degree even the well being of organs.
In gravity the human body functions more like a tent than like a house. The higher the degree of tensional integrity within the myofascial webbing, the more upright and usually painfree the 'human tent' will be..