The meridian system, also called channel network is a concept in traditional Chinese medicine about a path through which the life-energy is known as “qi” flows.

Despite ongoing research into the existence of meridians, no convincing scientific evidence has been put forward for their existence.

Major proponents of their existence have also not come to any consensus as to how they might work or be tested in a scientific context.

The meridian network is typically divided into two categories, the jingmai or meridian channels and the luomai or associated vessels (sometimes called “collaterals”).

The jingmai contain the 12 tendinomuscular meridians, the 12 divergent meridians, the 12 principal meridians, the eight extraordinary vessels as well as the Huato channel, a set of bilateral points on the lower back whose discovery is attributed to the ancient physician Hua Tuo.

The collaterals contain 15 major arteries that connect the 12 principal meridians in various ways, in addition to the interaction with their associated internal organs and other related internal structures.

The collateral system also incorporates a branching expanse of capillary-like vessels which spread throughout the body, namely in the 12 cutaneous regions as well as emanating from each point on the principal meridians.

If one counts the number of unique points on each meridian, the total comes to 361, which matches the number of days in a year, in the moon calendar system. Note that this method ignores the fact that the bulk of acupoints are bilateral, making the actual total 670.

There are about 400 acupuncture points (not counting bilateral points twice) most of which are situated along the major 20 pathways (i.e. 12 primary and eight extraordinary channels).

However, by the second Century AD, 649 acupuncture points were recognized in China (reckoned by counting bilateral points twice).

There are “12 Principal Meridians” where each meridian corresponds to either a hollow or solid organ; interacting with it and extending along a particular extremity (i.e. arm or leg). There are also “Eight Extraordinary Channels“, two of which have their own sets of points, and the remaining ones connecting points on other channels.

12 standard meridians

The 12 standard meridians, also called Principal Meridians, are divided into Yin and Yang groups. The Yin meridians of the arm are Lung, Heart, and Pericardium.

The Yang meridians of the arm are Large Intestine, Small Intestine, and Triple Burner. The Yin Meridians of the leg are Spleen, Kidney, and Liver. The Yang meridians of the leg are the Stomach, Bladder, and Gall Bladder.

The 12 standard meridians are:

  1. Hand’s Major Yin Lung Meridian
  2. Hand’s Minor Yin Heart Meridian
  3. Hand’s Absolute Yin Heart Protector Meridian
  4. Hand’s Minor Yang Triple Burner Meridian
  5. Hand’s Major Yang Small Intestine Meridian
  6. Hand’s Yang Supreme Large Intestine Meridian
  7. Foot’s Major Yin Spleen Meridian
  8. Foot’s Minor Yin Kidney Meridian
  9. Absolute Yin Liver Meridian
  10. Foot’s Minor Yang Gallbladder Meridian
  11. Foot’s Major Yang Urinary Bladder Meridian
  12. Foot’s Yang Supreme Stomach Meridian

Eight extraordinary meridians

The eight extraordinary meridians are of pivotal importance in the study of Qigong, T’ai chi ch’uan and Chinese alchemy.

These eight extra meridians are different from the standard twelve organ meridians in that they are considered to be storage vessels or reservoirs of energy and are not associated directly with the Zang Fu, i.e. internal organs.

These channels were first systematically referred to in the “Spiritual Axis” chapters 17, 21 and 62, the “Classic of Difficulties” chapters 27, 28 and 29 and the “Study of the 8 Extraordinary vessels” (Qi Jing Ba Mai Kao) by Li Shi Zhen 1578.

The eight extraordinary vessels are:

  1. Conception Vessel (Ren Mai)
  2. Governing Vessel (Du Mai)
  3. Penetrating Vessel (Chong Mai)
  4. Girdle Vessel (Dai Mai)
  5. Yin linking vessel (Yin Wei Mai)
  6. Yang linking vessel (Yang Wei Mai)
  7. Yin Heel Vessel (Yin Qiao Mai)
  8. Yang Heel Vessel (Yang Qiao Mai)


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