The body is an organic whole. It is the meridians and collaterals that connect the viscera, the body, the five sensory organs and the nine orifices together. The meridians internally pertain to the viscera and externally connect the limbs. Since the meridians are composed of various collaterals of different levels, they have formulated the whole body into a network. There are three basic ways with which the meridians to connect all parts of the body together.

The connection between the external and the internal as well as the viscera and other organs is mainly accomplished by the twelve meridians. On the one hand the twelve meridians and their branches accomplish such a connection by emerging from the external of the body and entering the internal of the body. On the other hand, they reinforce such a connection with the twelve branches, twelve tendons and twelve skin divisions.

The twelve meridians has formed six pairs of external and internal relationships which enable the zang-organs and the fu-organs in external and internal relationships to connect with each other. The meridians stemming from the viscera associate with several internal organs during their running processes. As a result each zang-organ or fu-organ is connected with several meridians.

The twelve meridians are connected with each other, follow a certain running and infusing order and together form a large circulatory system. The twelve meridians and the eight extraordinary vessels have formulated a crisscross network. The extensive association among the meridians and collaterals enables the body to become an organic whole.