Pi Gen Tumor Root

What does Pi Gen do?

Pi Gen is an extra point — it belongs to no channel, so it carries no channel-theory actions, and everything set out below comes from documented clinical use rather than from channel mechanics. In that documented use it exists for one purpose: it is the point on the low back recorded for pi — the sense of a hard, blocked fullness in the abdomen, and the palpable lumps and firm enlargements that older texts group under that heading. Its name says exactly that, and it is a narrow, single-purpose point.

• Recorded for abdominal glomus and palpable abdominal masses — the defining documented use. In classical terminology these are pi kuai, firm accumulations in the abdomen with a sensation of stuffed blockage; the texts describe the point as being needled at the "root" of such an accumulation.
• Recorded for enlargement of the liver and spleen — the indication carried in Sacred Lotus sources & references and in the standard reference literature. This is a historical indication from the mid-twentieth-century Chinese texts and is recorded here as traditional use, not as treatment of any diagnosed disease.
• Used locally for lumbar pain — a straightforward local use for a point sitting in the muscle of the low back, and in modern practice probably the more common of its two applications.
• Moxibustion is documented at this point — unusually for an extra point, the reference literature records moxibustion as applicable here, which fits its traditional association with cold, chronic, fixed accumulations.

A correction worth stating plainly. Pi Gen has been described as "moving qi and relieving stagnation in the upper and middle burner". That is channel and organ-theory language, and Pi Gen is on no channel — it has no five-shu, yuan, luo, xi-cleft, back-shu or front-mu classification, and a point beside the first lumbar vertebra is in any case nowhere near the upper burner. Our own earlier record carried that phrase and it has been removed. The points that genuinely carry that function are the front-mu and Back-shu points of the organs concerned: LIV-14 Qi Men, front-mu of the Liver, and LIV-13 Zhang Men, front-mu of the Spleen and meeting point of the yin organs, for accumulation below the ribs; REN-12 Zhong Wan, front-mu of the Stomach and meeting point of the yang organs, for glomus in the epigastrium; BL-18 Gan Shu and BL-20 Pi Shu on the back; and LIV-03 Tai Chong distally. All are held in Sacred Lotus sources & references, and all of them, unlike Pi Gen, have a documented channel and organ relationship to the abdomen.

Source: Sacred Lotus sources & references (existing action, indication and needling record, corrected as described; LIV-13, LIV-14, REN-12, BL-18, BL-20 and LIV-03 records); Chinese Acupuncture & Moxibustion (p. 247); cross-referenced against multiple online sources.

What is Pi Gen used for?

Pi Gen has one of the shortest indication lists of any point we hold. Sacred Lotus sources & references carry two indications — enlargement of the liver and spleen, and lumbar pain — and the wider reference literature adds little beyond closely related presentations. The list below is short because the sources are short; padding it would misrepresent the point.

• Abdominal glomus — a sensation of hard, stuffed blockage in the abdomen
• Palpable abdominal masses and accumulations (pi kuai)
• Enlargement of the liver and spleen, as recorded historically in the reference texts
• Fullness and distension below the ribs
• Lumbar pain, as a local point
• Chronic gastric and abdominal complaints, listed in some sources as a secondary use

These describe traditional use, not proven treatment. The historical indications in particular belong to a period when a palpable abdominal mass was a clinical category in its own right rather than a finding to be investigated, and they are recorded here for what the tradition documents.

Source: Sacred Lotus sources & references (existing indication record); Chinese Acupuncture & Moxibustion (p. 247); cross-referenced against multiple online sources.

How is Pi Gen used in practice?

Pi Gen sits low on the back, well out to the side of the spine — three and a half cun lateral to the lower edge of the first lumbar vertebra, which places it in the thick muscle beside the spine roughly a hand's breadth from the midline, just below the lowest rib. That is further out than either line of Bladder-channel points on the back. Sacred Lotus sources & references record that location and it is the standard one. The point is used on both sides.

Which points is Pi Gen combined with?

• With LIV-13 Zhang Men and LIV-14 Qi Men — the front-mu points of the Spleen and Liver, on the front of the body below the ribs. Where Pi Gen is used for accumulation below the ribs, these are the points that carry the organ relationship for it.
• With REN-12 Zhong Wan — front-mu of the Stomach and meeting point of the yang organs, the standard point for glomus and fullness in the epigastrium.
• With BL-18 Gan Shu and BL-20 Pi Shu — the Back-shu points of the Liver and Spleen, lying on the same back, higher up and closer to the midline. In practice these are reached for far more often than Pi Gen for the same presentations.
• With the Hua Tuo Jia Ji points — the paravertebral extra points running the length of the spine, which include a point at the same first-lumbar level much closer to the midline.
• With Wei Guan Xia Xu — the extra point at the eighth thoracic level, numbered EX-B 3 immediately before Pi Gen in the extra-point sequence, and the other back extra point recorded for the digestive tract. Both are held in Sacred Lotus sources & references.
• With BL-23 Shen Shu, DU-04 Ming Men and Yao Yan — the lumbar points, where Pi Gen is being used for local low back pain rather than for abdominal accumulation.

How does Pi Gen compare with the other extra points of the low back?

Sacred Lotus sources & references hold several, and they divide cleanly. Yao Yan ("Lumbar Eyes") sits at the fourth lumbar level in the visible dimples above the buttocks and is a low back point. Shi Qi Zhui Xia lies on the midline below the seventeenth vertebra. Yao Qi is lower still, above the tailbone. Hua Tuo Jia Ji runs the whole spine half a cun either side of the midline. Pi Gen is the odd one out: it is the only one of the group whose defining indication is not the back at all but the abdomen, and it is by some distance the least used of them.

Source: Sacred Lotus sources & references (location and existing use record; LIV-13, LIV-14, REN-12, BL-18, BL-20, BL-23, DU-04, Hua Tuo Jia Ji, Wei Guan Xia Xu, Yao Yan, Shi Qi Zhui Xia and Yao Qi records); Chinese Acupuncture & Moxibustion (p. 247); cross-referenced against multiple online sources.

Where is Pi Gen located?

• Chinese Acupuncture and Moxibustion (p. 247): 3.5 cun lateral to the lower border of L1

How is Pi Gen needled, and what does the literature record about depth?

Reference record only — this sets out what the standard texts document, not instruction for a reader. Sacred Lotus sources & references record perpendicular insertion of 0.5 to 0.8 cun at Pi Gen, with moxibustion applicable. That is a notably shallow range for a point sitting in the thick muscle of the low back — our own Yao Yan record, lower down the same back, carries 1 to 1.5 cun. The reason the recorded range here is short is worth understanding, and it is the most important thing on this page.

• Angle documented: perpendicular.
• Depth documented: approximately 0.5 to 0.8 cun.
• Moxibustion: documented as applicable, and traditionally favoured here given the point's association with chronic, cold, fixed accumulations.

What is the safety concern at Pi Gen?

Pi Gen is a lumbar point lateral to the spine, and the documented concern there is the one that applies across this region: deep needling can pass beyond the paraspinal muscles into the retroperitoneal space behind the abdominal cavity. Pi Gen sits at the first lumbar level, which places it higher on the back than most of the points that carry this caution — squarely within, rather than at the lower margin of, the territory the kidneys occupy. The following is what is actually documented, stated precisely.

• What the imaging work establishes. An MRI study of 61 healthy subjects measured both the "dangerous depth" and the effective safe depth of perpendicular and oblique needling at the acupoints of the kidney region — BL-21, BL-22, BL-23, BL-50, BL-51 and BL-52 — and found that safe depth varies substantially with body size: markedly greater in overweight subjects and markedly shallower in underweight ones, where the authors concluded that direction and depth must be restricted to avoid accident (Zhongguo Zhen Jiu 2022;42(9):1006–1010, PMID 36075596). Those points lie one and a half and three cun lateral to the midline, in the same band of the back as Pi Gen and at overlapping vertebral levels. The study does not measure Pi Gen itself, and we do not claim that it does — but it is the best-quantified evidence available that safe depth in this region is a function of the individual, not a fixed number.
• Where the kidneys actually are. The kidneys lie retroperitoneally, behind the abdominal cavity and in front of the lumbar muscles, spanning roughly the twelfth thoracic to the third lumbar vertebral levels; normal variation extends the range in both directions. Pi Gen is recorded at the first lumbar level — that is, within that span rather than below it. That is the accurate statement, and it is why we describe the hazard as retroperitoneal rather than asserting a renal injury risk we cannot source specifically for this point. What a reader should take from it is that the structures deep to Pi Gen are not muscle all the way down, and that the shallow depth the texts record is not arbitrary.
• The lowest ribs are close. The point sits just below the free end of the twelfth rib, and the lowest recess of the chest cavity descends behind the ribs to about that level. This is a further reason the recorded depth at this point is short, and it is why the reference texts describe perpendicular insertion into muscle rather than any angling upwards.
• What the case literature documents. Injury to retroperitoneal structures following acupuncture is recorded in the published case literature — including a retroperitoneal haematoma from rupture of a pseudoaneurysm caused by acupuncture (J Urol 1998;159(6):2087, PMID 9598531) and a retroperitoneal abscess complicating acupuncture (J Korean Med Sci 2003;18(5):756–757, PMID 14555834). Systematic reviews of acupuncture adverse events list traumatic organ injury among the small number of genuinely serious events on record and conclude that these overwhelmingly followed improper technique rather than acupuncture as such (Zhang et al., Bull World Health Organ 2010;88(12):915–921C, PMID 21124716, PMC2995190; Am J Chin Med 2024, PMID 39460372). A meta-analysis of prospective studies put serious adverse events at roughly one per 10,000 patients (BMJ Open 2021;11:e045961, PMID 34489268).
• Honest limit of what we can source. We could not locate any published caution or case report naming Pi Gen specifically. Rather than assert one or omit the subject, we record what is documented: a deliberately shallow depth in the reference texts, quantified evidence that safe depth in this region depends heavily on body size, and a published record of retroperitoneal injury from deep needling here.

Acupuncture is performed by qualified, licensed practitioners. This record documents what the literature states and is not a technique guide.

Source: Sacred Lotus sources & references (existing needling record; Yao Yan and BL-23 records, whose sourced kidney-region framing is applied here); Chinese Acupuncture & Moxibustion (p. 247); PubMed PMID 36075596, 9598531, 14555834, 21124716 (PMC2995190), 39460372, 34489268 — each verified resolvable and checked for retraction status before citation.

What does the name Pi Gen mean?

Pi Gen means "Root of the Glomus", commonly rendered "Tumor Root" — pi for a glomus, and gen for a root. The word that needs unpacking is pi. In classical Chinese medicine it names a specific complaint: a sensation of hard, stuffed blockage in the abdomen, sometimes with a lump that can be felt, sometimes without. The point's name says it is needled at the root of that blockage — the place on the back behind where the accumulation sits. The English rendering "Tumor Root" is the one our record carries and is a reasonable translation of the older sense of pi kuai, an abdominal accumulation; it should not be read as a claim about tumours in the modern medical sense, and no such claim is made here.

Is Pi Gen a channel point?

No. Pi Gen is an extra point, carrying the code EX-B 4 — "extra point, back, number 4" — which places it in the numbered sequence between Wei Guan Xia Xu (EX-B 3) and the lower back extra points. Extra points sit outside the fourteen channels: they were recorded for an observed clinical effect rather than derived from channel theory, so they carry no five-shu, yuan, luo, xi-cleft, back-shu or front-mu classification. That is why our record shows no channel and no point categories, and why the actions above are framed as documented uses. It is worth noting how far out from the midline it sits: at three and a half cun lateral it lies outside both lines of Bladder-channel points on the back, which is itself a marker that it was never part of the channel scheme.

Is there research on Pi Gen?

The honest answer is none. We searched the indexed biomedical literature for studies naming this point — under Pi Gen, Pigen, and the code EX-B 4 — and found no clinical trial, no case series and no mechanistic study specific to it. That is not a surprising result for a minor extra point with a narrow historical indication, and it is worth stating plainly rather than filling the space with studies of acupuncture for abdominal complaints that happen not to have used this point. Two things follow from it, and both are useful to a reader.

• Its standing is entirely traditional. Pi Gen appears in the modern extra-point compilations because it was recorded in earlier Chinese sources, and it has stayed there. Nothing has tested it. Where a point's reputation rests on a single classical indication and no modern use has grown up around it, that is the accurate description of its status.
• Its historical indication belongs to another era of diagnosis. Enlargement of the liver and spleen, and palpable abdominal masses, are today findings that lead to investigation rather than conditions treated in their own right. The tradition recorded what it observed with the tools it had. We record what the tradition documents, and we do not extend it.

Readers who arrived here looking for the acupuncture literature on digestive complaints will find far more of it at the front-mu and Back-shu points named above — REN-12 Zhong Wan, LIV-13 Zhang Men, LIV-14 Qi Men, BL-18 Gan Shu and BL-20 Pi Shu — and at ST-36 Zu San Li, all held in Sacred Lotus sources & references. A short accurate page on a minor point is better than a padded one.

Source: Sacred Lotus sources & references (name, location and existing record; REN-12, LIV-13, LIV-14, BL-18, BL-20, ST-36 and Wei Guan Xia Xu records); Chinese Acupuncture & Moxibustion (p. 247); PubMed and PMC searched for point-specific literature with no qualifying result; cross-referenced against multiple online sources.