A first year essay on the structure of the meridian system

This is part of an essay I did to try and define the function and structure of the meridian network of the body that we use in Chinese medicine. This is a very broad subject and there are thousands of books related to this subject, so this is a brief outline. This essay is probably a little heavy on the TCM theory and terminology side of things for someone who has never studied it.

The twelve main meridian channels that make up the Jing Luo all connect, and make up a pathway or circuit that allows for the flow and distribution of substances such as Qi and Blood (2). The channels are described by Kaptchuk (2) as not being blood vessels but rather ‘an invisible lattice that links together all the fundamental textures and organs’ (p.105). All the channels correspond or are rooted to an internal organ in the body. In meridian theory, (2) if there is a blockage or disturbance in a channel this can result in a dysfunction in a corresponding organ or vice versa.

The channels can be seen as a communication system between the organs and the external environment (4), as well as between the organs themselves. In channel theory it’s considered that where one channel ends another starts, in other words, it is a continuous network.

Wang Ju-Yi (4) explains that each channel has a specific functional depth within the body. Each channel is also paired with another which is at the same functional depth. The idea of functional depth, of which there are six, (Tai yang, Shao yang, Yang ming, Tai yin, Shao yin, Jue Yin) can be thought of as a group of systems, each having its own function, similar to that of western medicine in regards to the different systems that have been established, like the cardiovascular, endocrine, respiratory and so on (4). It’s ‘depth’ is based on energetic qualities, characteristics and functions, not physical depths. Each of these levels mentioned above, belongs to either the hand or foot grouping, therefore making 12 in total.

As well as the six levels of functional depth, each channel has its own layers within itself that are said to function at different levels. These layers are different to that mentioned above, and can be thought of as different levels of protection and communication. These are the Cutaneous regions, Minute collateral's, Sinew channels, Luo connecting channel, Primary channels, Divergent channels, Extraordinary channels and the deep pathways of the Divergent channels.

The different layers of each channel not only act as communication networks for the body, but also act as defense lines against pathogenic influences. The first layer, or Cutaneous region of a channel is the first line of defense against pathogens. If (5) a pathogenic influence is not contained or does not get turned away buy this layer, the next level will be affected and so on.

A useful analogy to help imagine the whole system of organs and channels is one put forward (5) of a plant, or as I like to think, a fruit tree. ‘The zangfu (organs) may be perceived as the roots of the channels, the different channels themselves as the stems (trunks and branches), and the different body tissues, and especially the sense organs, as the flowers’ (5) (p.12) .

The first or most superficial layer is the cutaneous level of the channel. This channel is at the level of the skin and is there to stop pathogenic influences or energies from penetrating the Jing luo into the deeper levels. The cutaneous region is not a channel as such, but more a region or area. ‘Cutaneous regions also manifest disorders of the deeper lying channels, for example by abnormal skin sensations, skin lesions or discoloration’ (5) (p.27). In the analogy of the tree, the cutaneous region might be seen as the leaves, or the bark on the outer trunk. The next level known as the minute collaterals can be thought of as ‘the small and numerous branches or twigs of a big tree’ (4). These channels are often thought of as being the small capillaries near the surface of the skin. But as mentioned, the ‘the concept of channels is larger than that of blood vessels’ (4) (p.508). The minute collaterals have the function of connecting all tissue and substances that fall outside of the reach of the main flow of the primary channels, completing the internal external connection.

The twelve Sinew channels take their name from and are associated with the twelve primary channels (5). These channels are closely connected to the muscles tendons ligaments and tissues that follow the main channel pathway, (1) but are wider. The channels can also be injured by pathogenic influences. These channels originate at the extremities, and the Qi of these channels (1) gathers or binds at the joints and tendons.

The Luo connecting channels are described as ‘pathways that connect channels that are internally externally paired (5). For example the lung channel and the large intestine channel are internally / externally paired, and therefore are also connected via a Luo connecting channel (5).

Primary channels are the ones we visualize when we are thinking about acupuncture point location. The Primary channels run vertically, bilaterally and symmetrically, and the acupuncture points are located along the pathways of these meridians (5). These channels are the channels that connect the zangfu with the acupuncture points.

The Divergent channels serve as ‘internal linkages’ (5) that are not otherwise made by the other levels of the channel. ‘They connect or integrate parts of the body not supplied or integrated by the primary channels’ (5) (p.17). John E Pirog (6) states that the ‘meridian divergences, although listed as separate meridians in most acupuncture books, were really only branches of the main meridians’ (6)(p33). Another principle function of these meridians is to strengthen the internal external partnership or pairing of the zangfu by connecting them via divergent channels.

In addition to the 12 main meridians that are generally thought of when we are talking acupuncture points on the skin surface there are also eight Extraordinary meridians. These are the Du, Ren, Chong, Dai, Yinwei, Yangwei, Yinqiao and yangqiao.

One of the main functions of these channels is to

‘store, supply and regulate the qi and blood of the twelve main meridians. Therefore, when the qi and the blood of the twelve main meridians and zangfu organs are sufficient, the eight extra meridians store them and then supply the qi and blood to meet the active demands of the bodys functions’ (1) (p.36).

Only the DU and Ren channels have their own points, all the others share points of the twelve main channels. As well as being the only two of the eight extra channels to have their own points, the Du channel is also known as ‘the sea of yang’ (1), because it meets with all the yang channels. The Ren channels is known as ‘the sea of yin’ (1), because it meets with all of the Yin channels. These eight are thought to strengthen, bind together and affirm the main meridian structure.

It is now possible to see how all these layers all work to nourish, act as a barrier, transport qi and blood and act as communication channels between the external environment and the zangfu.

(1) Mao-liang Q. (ed) Chinese Acupuncture and Moxibustion. Singapore: Churchill Livingstone; 1993.

(2) Kaptchuk T. The Web That Has No Weaver, understanding Chinese medicine. New York: Mcgraw-Hill; 2000.

(3) Unschuld P. Medicine in China, Nan-Ching, The Classic of Difficult Issues. Berkely: University of California Press; 1986.

(4) Ju-Yi W, Robertson J D. Applied Channel Theory in Chinese Medicine, Wang Ju-Yi’s Lectures on Channel Therapeutics. Seattle: Eastland Press; 2008.

(5) Deadman P, Al-Khafaji M, Baker K. A Manual of Acupuncture. Hove: Journal of Chinese Medicine Publications; 2007.

(6) Pirog J. The Practical Application of Meridian Style Acupuncture. Berkly: Pacific View Press; 1996.