Channels and collaterals are a significant part of human tissues and structure. Channel and collateral theory is an important part of TCM , and combines basic theories such as yin-yang and five elements theory , visceral manifestation theory , qi-blood-fluid theory. Therefore , channel and collateral theory completely reflects TCM’s basic views on human physiology and pathology.

In the past , doctors repeatedly tested theories based on their observations of physiological and pathological phenomena. From this , they drew conclusions that were gradually purified and developed into the academic theory known as the theory of channels and collaterals. This is not only the theoretical basis of acupuncture , massage and qigong , but is of significance in guiding clinical diagnosis and treatment. Just as stated in the chapter “Channels and Collaterals” in the Spiritual Pivot (Lingshu) ,“The channels are important for determining life and death, treating various diseases and regulating deficiency and excess. Hence it must be thoroughly understood.”

The Concept of Channels and Collaterals

The channels and collaterals are special tissues, structures and limbs are connecting systems through which qi and blood circulate ,and through which the viscera and limbs are connected. The channels and collaterals allow the upper-exterior portions of the body to communicate ; adjusting the functional activities of all portions of the body.

Channels and collaterals are the general terms referring to the channel vessels and collateral vessels.The chapter of Start – stop in ELementary Medicine (Yixue Rumen ) states that “the channel means pathway, while the branches separating from the channels are called collaterals.” This means that the channels from a trunk, while the collaterals represent the branches. Most of the channels run through the deep portions of the body, while their collaterals go to shallower portions, some of which are exposed on the body. As the chapter of Channels and Collaterals in Spiritual pivot states, “The twelve regular channels run deeply in the boundary between muscles, and interiorly within the body…The collaterals run closer to the surface of the body, and are more easily seen. ”Channels run in straight fixed courses, while collaterals crisscross in the body, forming a network to link together the viscera, organs, orifices, skins, muscles, tendons and bones into an organic whole, thus guaranteeing the normal and vital movement of the human body.

The Composition of Channel and Collateral System

The channel and collateral system consists of Channels, Collaterals and other Affiliated Portions.

Classification of the channel and collateral system

Channels

Channels are the main trunk of the channel-collateral system. They can be divided into two types : regular channels and extraordinary channels. In addition , channel divergences are also included in the channnel-collateral system.

There are twelve regular channels ,including the three yin channels of the hands and the feet , and the three yang channels of the hands and the feet . These are generally termed “ the twelve regular channels. ”They are the main pathways in which qi and blood circulate. The twelve regular channels originate and terminate in certain areas. They also have a specific course and a sequence of circulation. There is a method to their distribution as they pass over and through the trunk and limbs and they connect with the viscera directly in the body’s interior. It is stated in the chapter of Discussion on Sea in Spiritual Pivot , “The twelve channels are internally related to the zang-viscera and fu-viscera , and externally connected with the limbs and joints .”

In addition to the twelve regular channels , the extraordinary channels are also important channels. There are eight channels that , collectively , are termed “the extraordinary channels.”These are the Du ( Governor Channel ) , Ren ( Conception Channel ) ,Chong , Dai , Yinqiao , Yangqiao , Yinwei , and Yangwei. They have the functions to govern , communicate , and regular qi and blood within the twelve channels. The book General Collection for Holly Relief (sheng Ji zong Lu ) states ,“Channels can be divided into the extra and the regular , the twelve channels belong to the regular, and the eight channels are different from the regular , as they go along additional courses. The qi and blood of the human body run along the twelve regular channels and flows into the extraordinary channels while the regular ones are full. ” The twelve divergent channels are categorized as channels because their running paths are deep and long.

Collaterals

Collaterals are branches of channels. Their pathways are shallower than the channels. Collaterals are classified as divergent , superficial , or minute. The divergent collaterals are larger and are considered major collaterals. The superficial collaterals run superficially and often appear at the surface. The minute collaterals are the tiniest collaterals. Except for divergent collaterals , most have no certain pathway. The branches of the collaterals gradually become smaller , turning into minute collaterals. These extend from threadiness to facet , thus closely connecting all parts of the tissues of the human body.

Affiliated Portions

The sinew channels and cutaneous regions are the affiliated portions in the tendons , muscle and the skin. They are closely connected to the channels and collaterals. Channel-Collateral theory holds that the sinew channels are the system whereby the channel-qi concentrates , accumulates , distributes , and connects with the tendons , muscles and joints. Their function is to connect limbs and bones , as well as control joint movements. The skin of the whole body represent the superficial regions of the twelve channels and collaterals. Therefore ,the skin throughout the entire body is divided into twelve parts that respectively belong to each of the twelve channels.