According to traditional Chinese medicine (TCM) concepts,the energy force, known as Qi, runs through the body. Qi energy enters the body through specific acupuncture points and flows to deeper organ structures, bringing life-giving nourishment of a subtle energetic nature. Meridians are classified on the basis of the direction in which Qi flows on the surface of the body. If the flow of Qi is insufficient, or interrupted, Yin and Yang become unbalanced and illness may occur. However, the ancient concept of Qi and meridians has no counterpart in modern studies of chemistry, biology, and physics.
Acupuncture is believed to restore the balance of Yin and Yang. Acupuncture loci, also know as acupoints, are the skin needling points used for acupuncture treatment. In humans, more than 300 acupoints are located along the meridians. Acupoints are thought to be specific points reflecting visceral conditions and organs. Despite the fact that specific acupoints are used for treating specific symptoms and/or diseases, it is not fully understood how their specificity is determined and how the needling at acupoints works. There was no clear evidence to demonstrate the existence of acupuncture points or meridians.