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. Those fourteen carry the 361 classical points that the WHO nomenclature fixed in part 1 of its 1991 revision.

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.

AcuiQ pads the ordinal to two digits and prints it that way everywhere: LI04, not LI4, and MS06, not MS6. Published papers pad inconsistently, so lookups here accept either form and resolve to the padded one. /points/li4 and /points/li04 are the same page.

Points off the channels

Not every named point sits on a channel. The extra points are grouped by region, and the WHO standard codes them 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. They are set out, with the scalp lines, in part 2 of the same revision.

This catalogue does not use that prefix. It carries the same five regions under a shorter form – XH, XB, XC, XU, XL – and keeps the WHO numbering underneath it, point for point. Yintang between the eyebrows is EX-HN3 in the standard and XH03 here. Taiyang at the temple is XH05. An EX- code will not resolve on this site, so a code carried in from a paper has to be converted before it will find anything.

One more rule applies only to the extras. Several of them are not a location but a set of them, and the set is coded with a trailing letter: Sishencong, the four points around the vertex, runs XH01A to XH01D, and Bafeng, the eight points between the toes, runs XL10A to XL10H. Xiyan, the eyes of the knee, is XL05A and XL05B. A bare XL05 is not a point in this catalogue, which is the kind of detail that decides whether an extracted prescription lands with the right number of needles in it.

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, MS01 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

Eight prefixes 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 ear has no row in that table, because the WHO nomenclature does not contain the ear. Its two parts cover the channels, the extra points and the scalp lines and stop there, and the one WHO meeting that did address auricular points met in Lyon in 1990 and adopted a partial list. This catalogue keeps its own auricular numbering, which does not match the standard most papers follow. The two schemes share the region prefixes AH, AT, TF and HX and disagree about the numbers under them, so an ear code carried in from a paper does not fail here: it resolves to a different real point. 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.