“Jing-Luo” is a general collective term for the pathway that the body’s energy or Qi circulates through. “Jing” originally means “boulevard” or refers to the main trunk and is translated into “Meridian,” while “Luo,” bearing the original meaning of “connecting lane,” pertains to the branches of the meridian and thus is translated to “Collateral.” Together Jing and Luo form a network and link all the body parts into an organic whole.
The Jing-Luo system is an important component of TCM basic theories that studies its distribution, physiology, pathology, and inter-relations with internal Zang-Fu organs. It was developed in China from ancient long-term clinical practice and it is still one of the theories guiding TCM diagnosis and treatment, especially the practice of acupuncture.
The Jing-Luo system consists of Jing, or meridians, and Luo, or collaterals. The meridians include 12 regular meridians that are considered as the major trunks and 8 extraordinary meridians. Attached to the 12 regular meridians are 12 divergent meridians, 12 muscle regions, and 12 cutaneous regions. The Luo system includes 15 collaterals, plus superficial floating and minute collaterals.
The names of the 12 regular meridians have three aspects: a Zang or Fu organ, hand or foot, and Yin or Yang. This is based on their distributing features within the body. Those running on the medial part of the limbs are named with “Yin” and belong to Zang organs, and those on the lateral belong to Fu organs and are thus named with “Yang.” For example, the meridian traveling on the medial part of the arm on the radial side belongs to the Lung, a Yin or Zang organ, and therefore is defined as the Lung Meridian of Hand Tai-Yin.
The 8 extraordinary meridians are named individually according to their functions. They are Du or Governing, Ren or Conception , Chong or Vital Pass, Dai or Girdle, Qiao or Heel (there are two Qiaos: Yin Qiao and Yang Qiao), and Wei or Connecting (Yin Wei and Yang Wei).
Moreover, the 12 divergent meridians, muscle regions, and cutaneous regions are named with “Yin” or “Yang,” and with “hand” or “foot.”