The fifteen Luo meridians
The fifteen Luo meridians: the connecting channels of the meridian system
In addition to the twelve Primary Meridians, TCM recognises fifteen Luo meridians — also called Connecting Meridians or Collaterals. They are narrower than the Primary Meridians, run transversely through the body and fulfil a crucial connecting role: they link the paired Yin and Yang meridians with one another and thereby make direct energetic exchange between the two possible. Whoever understands the Luo meridians understands a layer of meridian anatomy that is of great therapeutic importance in clinical practice.
The fifteen Luo meridians: composition
The fifteen Luo meridians consist of three groups. The first group comprises the twelve Luo meridians belonging to each of the twelve Primary Meridians — one for each meridian. The second group consists of two Luo meridians arising from the Extraordinary Meridians: the Ren Mai Luo and the Du Mai Luo. The third is the Great Luo meridian of the Spleen (Spleen Great Luo, Spleen 21) — a particularly powerful Luo meridian that reaches the entire thorax and has a regulating function over the overall Yin-Yang balance of the trunk.
The Luo point: the gateway
Every Primary Meridian has one specific Luo point — an acupuncture point from which the Luo meridian arises and spreads. From this Luo point, the Luo meridian connects with the internally-externally paired meridian. The Lung meridian (Yin), for example, is paired with the Large Intestine meridian (Yang): the Luo point of the Lung (Lung 7, Lieque) is the point from which the Lung Luo meridian arises and extends toward the Large Intestine meridian. By treating the Luo point, the acupuncturist can directly influence the relationship between the two paired meridians.
Functions of the Luo meridians
The Luo meridians fulfil two main functions. First, they strengthen the relationship between the internally-externally paired Primary Meridians and the corresponding organs — they are the bridges that connect the Yin and Yang sides of an element. Second, each of the fifteen Luo meridians has its own specific pathway and its own specific therapeutic qualities. The Luo meridian of the Lung spreads toward the thorax and chest; that of the Liver reaches the genital organs; that of the Spleen extends over the entire abdomen. Each Luo pathway reflects the unique connecting function of that specific meridian pairing.
Clinical application
In practice, Luo points are used when there is a disorder involving both paired meridians — or when the disorder is more superficial and concerns the Luo layer rather than the deep Primary Meridian. Luo points are also particularly effective in chronic, long-standing complaints where the pathogen has become lodged in the Luo layer. The Great Luo meridian of the Spleen (Spleen 21) is used for general pain or weakness of the muscles and thorax, and is a powerful tonification point for the entire Spleen function.