An erect posture is maintained by spinal, abdominal, leg and other supportive muscles. In fact the entire musculature of the body participates in maintaining the body's posture in some way or the other. We will see in the following chapter how exactly this is carried out. The weight-bearing function of the various muscles determines the state of the joints, discs, bones etc. The wear and tear of these structures depend on how well the muscles carry the body's weight in rest, stress, exercises and at work. The integrity of the spine, in its influence on nerves and blood vessels, determines the performance of every system of the body. Only if we accept this will it become clear how much we depend upon our backs, and the extent to which we need a gatekeeper, or complete General Practitioner, to guide us to the right specialist. Conventional medicine, represented by orthopaedic surgeons in matters of back problems, seems to think that discs and joints are the root cause of most back-related problems and that such problems are confined to the back. We will argue and logically try to prove that this concept is a long way from the truth. But first let us consider how muscles work.