Meridians refer to the meridians and collaterals, which in Chinese medicine are called the twelve meridians and fifteen collaterals. The two, together with the eight odd meridians and the twelve meridians, constitute the meridian system. 1. Twelve meridians: the main component of the meridian system, linking the inside and outside of the body into an organic whole. The main components are the Taiyin Lung Meridian, the Syncopal Pericardium Meridian, the Shaoyin Heart Meridian, the Yangming Large Intestine Meridian, the Shaoyang Sanjiao Meridian, the Sun Small Intestine Meridian, the Taiyin Spleen Meridian, the Syncopal Hepatitis Meridian, the Shaoyin Kidney Meridian, the Yangming Stomach Meridian, the Shaoyang Bile Meridian, and the Sun Urinary Bladder Meridian. 2. Fifteen channels: connected to the twelve meridians, they mainly play a role in communicating the qi and blood of the two meridians and supplementing the deficiencies of the meridian circulation. Its composition is mainly composed of the twelve meridians in the limbs of each branch of a complex, which is the twelve complexes, plus the front side of the torso of the Ren vein complex, the back side of the torso of the Governor vein complex and the side of the torso of the Spleen of the large complexes, constituting the fifteen complexes.