Reading a point code

A point code looks like a catalogue number and behaves like a street address. Both halves carry meaning, and both halves are only meaningful inside a system that has already been named. LI04 is the fourth point on the Large Intestine channel, counting from where the channel starts. Knowing the number without the channel is knowing a house number without the street.

The shape of a code

Codes on the main channels are an abbreviation followed by an ordinal. The abbreviation names one of the fourteen channels that carry points of their own – the twelve organ channels, plus the Conception and Governing vessels. The ordinal counts along the channel in a fixed direction, so the first and last points are landmarks: the Lung channel runs LU01 below the collarbone to LU11 at the thumbnail, and the Bladder channel runs BL01 at the inner corner of the eye to BL67 at the little toe.

The ordinal is not a ranking and carries no clinical weight. LI04 is not more important than LI20 because it comes first; it is closer to the index finger.

Points off the channels

Not every named point sits on a channel. The extra points are grouped by region and coded with an EX- prefix: EX-HN for head and neck, EX-B for back, EX-CA for chest and abdomen, EX-UE for upper limbs, EX-LE for lower limbs. Yintang between the eyebrows and Taiyang at the temple are both EX-HN. Xiyan at the knee is EX-LE.

Two families are coded differently again because they are not points in the same sense. The auricular points map regions of the body onto the outer ear. The scalp lines, MS1 to MS14, are lines over cortical projection areas rather than positions on a channel, and are needled along their length rather than at a spot.

Where AcuiQ differs from the WHO standard

Three channel abbreviations in this catalogue are not the WHO ones. They are the forms that dominate the English-language literature AcuiQ reads, and changing them would have made the catalogue disagree with its own sources.

The auricular numbering diverges more widely. This catalogue keeps its own numbering, which does not match the international standard everywhere, and the divergence is published as a crosswalk rather than reconciled in silence.

Why the prefix is load-bearing

A code that cannot be resolved raises an error, and somebody sees the error. A code that resolves to the wrong point raises nothing at all. Across 48,579 point references extracted from the literature, 37 resolved silently to a point the author did not mean – not because any standard is wrong, but because a published code carries no namespace saying which standard it belongs to. The measurement, and the crosswalk that fixes the auricular half of it, are in TF4 Is Not a Point.

The practical consequence for a reader is small and worth holding: when you carry a code out of one source and into another, carry the source with it. A bare ordinal survives the journey. Its meaning does not.