According to the traditional Chinese philosophy, yin and yang produced the five elements, and all matter was fashioned from these elements. It was further imagined that the elements must have their parallels in the human body. Wood, fire, earth, metal and water correspond to the liver, heart, spleen, lungs and kidneys, respectively. According to the Chinese medical theory they are the solid organs. Each solid organ has a corresponding hollow organ. They are, in order, the gall bladder, small intestine, stomach, large intestine and urinary bladder. Solid organs are yin, while hollow organs are yang in functions and characteristics.
- Fire symbolises heart, small intestine, pericardium and triple warmer;
- earth symbolises stomach and spleen;
- metal stands for lung and large intestine;
- water symbolises kidney and urinary bladder and
- wood represents liver and gall bladder.
These five elements are constantly transformed into one another and there are two cycles of events in this process of transformation-the creative and the destructive cycles. According to the creative cycle earth forms metal, metal melts into water, water leads to the creation of wood, wood creates fire by burning, and fire gives rise to earth (ashes). According to the destructive cycle the metal cuts wood, wood eats earth, earth destroys water, water destroys fire and fire destroys metal.
The same principle is applied to the related organs in the body. The vital energy chi follows certain definite rules in respect of the direction, time and side of the body. According to one rule known as mother and son law, it flows from-mother to son and in sequence. The’ kidney is the mother of liver and liver is the mother of heart. Similarly according to other rule (husband-wife law) husband dominates over the wife;organs related to the husband are small intestine, heart, gall bladder, liver, urinary bladder, and kidney while those related to the wife are large intestine, lung, stomach, spleen, triple warmer and pericardium.
The flow of energy follows certain rules in relation to timing also . The rule pertaining to this is known as the mid-day, mid-night law. The circulation of energy is shown in a chart known as organ clock.
The traditional Chinese concepts, which were supposed to be mere imaginations, received a strong support from the Kirlian photography of Russians and researches by Korean scholars. Kirlian photography is a Soviet invention made way back in 1939 by S.D. Kirlian and V. Kirlian. In this technique a living being is observed and photographed under high frequency and high voltage electrical fields. The photograph shows a halo and it is suggested that this halo is the energy flow of chi. The Korean scholars (Kim Bong Han and coworkers) have injected acupuncture points with a radio-isotope and watched its flow. They could demonstrate the flow of fluid in the path or meridians. Besides the age -old traditional Chinese theories, there are many modern theories also put forward by some master minds who have a grip of both the fields-the acupuncture and the modern medical science. This is an endeavor to explain the acupuncture effect in the light of modern medical science of physiology. The most important amongst many are the theories put forward by Anton Jayasuriya and Fernando (1977), Ronald , Melzack and Wall (1963) and Pameranz (1976). Anton Jayasuriya and Fernando have put forward the motor gate theory, Ronald Melzack and Wall have put forward gate control theory while Pomeranz has suggested the theory of endorphin release.