A great analogy is that of a kink in a hose. If you try to water your garden with a kink in the hose the water cannot get from the source through the hose to the garden unimpeded. This results in less growth and healing of the garden. Same concept with the body when the nerves are impinged by subluxations in the spine the correct signal from the brain to the rest of the body is impeded and results in pain or dysfunction.