Discussion on Meridians from the Theory of Yang at Abdominal Side and Yin at Back Side

When studying the ancient literature on meridians,we found original meridians' distribution in Silk Book conforms to the principle of yang belonging to abdominal side and yin belonging to back side which was used for defying yin or yang nature of objectives before Qin Dynasty.Similar indications can also be found in The Yellow Emperor's Inner Classic.However,due to the shortage of this principle,the opposite theory that the back belongs to yang while the abdomen belongs to yin was produced,which allows foot-yin meridians to extend to abdomen,foot-yang meridians to have extra branches,and includes back-shu points of the viscera.