In the TCM system of medicine, the body is seen as a delicate balance of two opposing and inseparable forces: Yin and Yang. Yin represents the cold, slow, or passive principle, yang represents the hot, excited, or active principle. In TCM, health is achieved by maintaining the body in a “balanced state” and that disease is due to an internal imbalance of Yin and Yang. This imbalance leads to blockage in the flow of Qi (vital energy) along the meridians of which there are 12 main meridians and 8 secondary meridians. It is believed that more than 2,000 acupuncture points on the human body that connect with them.