REN-19 (Zi Gong) Purple Palace

What does REN-19 Zi Gong do?

Zi Gong REN-19 is a local chest point on the Conception Vessel whose recorded action is to unbind the chest and turn rebellious qi downward. It lies on the breastbone itself, on the midline, and its clinical range follows what sits behind it — the lungs, the airway and the heart. Its actions are those of a local point, and no special-point category is recorded for it.

• Unbinds the chest — the primary recorded action, for the sense of a tight, blocked or oppressed chest. Chinese medicine treats this constricted feeling as a thing in its own right, distinct from pain, and the sternal points of the Conception Vessel are the classic local answer to it.
• Regulates and descends qi — for qi that rises when it should fall: cough that will not settle, wheezing, and the shortness of breath that accompanies a congested chest.
• Alleviates chest pain — the local action along the midline of the sternum.
• Benefits the throat and diaphragm — a secondary use recorded in the reference literature, for a sense of obstruction at the level of the gullet and for difficulty swallowing, on the reasoning that the Conception Vessel runs the length of the front midline through both.

Zi Gong belongs to the run of Conception Vessel points spaced down the breastbone — Xuan Ji REN-21, Hua Gai REN-20, Zi Gong REN-19, Yu Tang REN-18, Shan Zhong REN-17 — which share a single functional identity: they are the chest's local points, and their names collectively describe the imperial palace complex that the classics place over the heart.

Source: Sacred Lotus sources & references (existing action record); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 520); Chinese Acupuncture & Moxibustion (p. 240); cross-referenced against multiple online sources.

What is REN-19 Zi Gong used for?

Zi Gong REN-19 is used for the chest — pain, tightness, cough and wheezing. The indications carried in Sacred Lotus sources & references are pain in the chest, asthma and cough; the standard reference literature sets them out as follows. These describe traditional use, not proven treatment, and this point carries the sternal cautions set out under needling.

• Pain in the chest
• Fullness, tightness and oppression of the chest
• Cough
• Asthma and wheezing
• Shortness of breath and difficult breathing
• Coughing of phlegm or blood-streaked phlegm
• Difficulty swallowing; a sense of obstruction in the gullet
• Loss of appetite and inability to take food, in the classical lists
• Vomiting
• Sore throat

Source: Sacred Lotus sources & references (existing indication record); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 520); Chinese Acupuncture & Moxibustion (p. 240).

Where is REN-19 Zi Gong, and how is it used in practice?

Zi Gong sits on the front midline, on the body of the breastbone, level with the second intercostal space — that is, level with the junction between the second rib space and the sternum. Sacred Lotus sources & references place it there in both of the location records held for the point. Counting from the sternal angle, the palpable ridge where the manubrium meets the body of the sternum, it is one rib space below. It is a straightforward point to locate and a comparatively minor one in daily practice — the sternal points are used less often than the far more prominent Shan Zhong REN-17 four spaces below it.

Which points is REN-19 combined with?

• For chest oppression and cough — with Shan Zhong REN-17, the front-mu point of the Pericardium and the Meeting Point of Qi, which is the principal chest point and the one REN-19 supports rather than replaces.
• For wheezing — with Tian Tu REN-22 in the suprasternal notch above it and Fei Shu BL-13, the Lung back-shu point behind; with Ding Chuan, the extra point held here at the base of the neck, in modern practice.
• With its own neighbours on the sternum — Yu Tang REN-18 immediately below and Hua Gai REN-20 immediately above; the sternal points are commonly used as a short vertical series joined by transverse needling rather than singly.
• For descending rebellious qi — with Nei Guan PC-06 at the wrist, the confluent point of the Yin Linking vessel and the standard distal point for the chest, and with Feng Long ST-40 where phlegm dominates.

Where does REN-19 sit among its peers?

REN-19 carries no five-shu, yuan, luo, xi-cleft, back-shu, front-mu or confluent classification in Sacred Lotus sources & references, and none has been invented for it here. It is one of the four sternal Conception Vessel points between Tian Tu REN-22 at the throat and Shan Zhong REN-17 between the nipples. All four share the same actions, the same territory and the same needling restriction; they are chosen by which rib space the practitioner wants to reach rather than by any difference in function.

Source: Sacred Lotus sources & references; Deadman & Al-Khafaji, A Manual of Acupuncture (p. 520); Chinese Acupuncture & Moxibustion (p. 240); cross-referenced against multiple online sources.

Where is REN-19 located?

• A Manual of Acupuncture (p. 520): On the midline of the sternum, level with the junction of the second intercostal space and the sternum.
• Chinese Acupuncture and Moxibustion (p. 240): On the anterior midline, at the level with the second intercostal space.

How is REN-19 Zi Gong needled, and why is perpendicular insertion ruled out?

Stated plainly: REN-19 lies on the breastbone, and the reference literature records insertion at the sternal points as transverse or oblique only — never perpendicular. The reason is not simply the thickness of the bone. A minority of people are born with a sternal foramen, a small congenital hole through the breastbone, and a needle passing through it can reach the pericardium and the heart. A fatal case is on record. Everything below is recorded as neutral reference data describing what the textbooks and the anatomical literature state. It is not instruction, and this page does not teach technique. Needling is carried out only by a qualified, licensed practitioner.

The angle and depth the texts record

• Sacred Lotus sources & references record subcutaneous (transverse) insertion of 0.3 to 0.5 inch, with moxibustion applicable. "Subcutaneously" is the operative word: the needle is recorded as running just under the skin along the surface of the bone, not into or toward it.
• Chinese Acupuncture & Moxibustion (p. 240) and Deadman & Al-Khafaji (p. 520) both record transverse or oblique insertion at the sternal Conception Vessel points, in a comparable shallow range.
• All three records agree on the same restriction, which is unusual and worth noting: for most points the sources differ on depth, but for the sternum they converge on transverse-only.

The sternal foramen

A sternal foramen is a congenital opening left where the two halves of the sternum fail to fuse completely during development. It is harmless in itself, causes no symptoms, and most people who have one never know. It matters here for one reason: it is a hole straight through the front wall of the chest, and immediately behind the sternum lie the pericardium and the heart.

• How common is it? Published imaging series put the prevalence of a sternal foramen at roughly 5 to 13 per cent, varying by population and by how it is defined. A multidetector CT study of 1,150 living patients found sternal foramen in 4.9 per cent, and reported that the sternal and xiphoidal foramina it identified lay adjacent to the pericardium in 37 per cent of cases (Eur J Radiol 2021;142:109828, PMID 34280594, DOI 10.1016/j.ejrad.2021.109828). A CT series of over 1,000 patients found sternal foramen in 9.6 per cent (Clin Anat 2022, PMID 35385153). A CT study explicitly framed around avoiding fatal complications of sternal puncture and sternal acupuncture found a midline sternal foramen in a risk-bearing configuration in about 10.5 per cent of 114 chest computed tomograms, and its authors recommended the superficial-oblique approach to the sternum for exactly this reason (Surg Radiol Anat 2015;37(3):287–91, PMID 25023390, DOI 10.1007/s00276-014-1339-x). A comparative CT study of 1,334 indigenous Bolivian participants against 703 North American participants found 12.8 to 13.4 per cent in the Bolivian groups against 4.4 to 5.1 per cent in the US groups, and a consistently higher rate in men than in women (Anat Sci Int 2021, PMID 34053001).
• The documented fatal case. A case report in The Lancet records fatal cardiac tamponade — bleeding into the sac around the heart — after acupuncture passed through a congenital sternal foramen (Lancet 1995;345(8958):1175, PMID 7723561, DOI 10.1016/s0140-6736(95)91004-2). This is the case the anatomical literature returns to whenever sternal foramina are discussed, and it is why radiology reviews of sternal variation name acupuncture alongside bone-marrow aspiration as a procedure the variant matters for (Indian J Radiol Imaging 2016, PMID 27413263). A German radiological paper on the variant was titled, translated, "the foramen sternale: a minor anomaly — great relevance" (Rofo 1997, PMID 9072108).
• Where in the sternum? The foramen is most often reported low in the body of the sternum, toward the xiphoid end — nearer the lower Conception Vessel chest points than to REN-19 itself, which sits high on the sternal body at the second intercostal space. That does not narrow the rule: because the variant is invisible from the surface and its position cannot be predicted, the transverse-only convention applies across the whole breastbone.

The proportion of the risk

This is a rare event. A meta-analysis of prospective clinical studies estimated serious adverse events in acupuncture at approximately 1 per 10,000 patients and around 8 per million treatments, concluding that acupuncture is among the safer treatments in medicine (Bäumler P et al., BMJ Open 2021;11:e045961, PMID 34489268). The sternal foramen hazard is best understood not as a common danger but as the precise reason a long-standing technical convention exists: the texts have always recorded sternal points as transverse-only, and modern anatomy has since supplied the mechanism.

Source: Sacred Lotus sources & references (existing needling record); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 520); Chinese Acupuncture & Moxibustion (p. 240); PMID 7723561; PMID 25023390; PMID 34280594; PMID 35385153; PMID 34053001; PMID 27413263; PMID 9072108; PMID 34489268 — each record checked as active and not retracted.

What does the name Zi Gong mean?

Zi Gong here means "Purple Palace" — zi, purple, and gong, a palace. In Chinese astronomy the Purple Forbidden Enclosure is the circumpolar region of the sky around the pole star, the celestial seat of the emperor. The Conception Vessel points on the breastbone are named as an imperial complex laid over the heart, which classical Chinese medicine calls the ruler of the organs: Xuan Ji REN-21, the jade pivot of the heavens; Hua Gai REN-20, the emperor's canopy; Zi Gong REN-19, the purple palace itself; Yu Tang REN-18, the jade hall. The name is a statement of anatomy through metaphor — this is the point over the sovereign's residence.

Is REN-19 Zi Gong the same as the Zi Gong "uterus" point?

No — and this is the single most confused pair of names in the point repertoire. They are two entirely different points that share a transliteration.

• Zi Gong REN-19 — 紫宮, "Purple Palace." On the Conception Vessel, on the breastbone, level with the second intercostal space. Used for the chest: cough, wheezing, chest pain. Nothing to do with gynaecology. This page.
• Zi Gong Xue — 子宮穴, "Palace of the Child," that is, the Uterus. A bilateral extra point on the lower abdomen, held separately in Sacred Lotus sources & references, located 3 cun lateral to the midline level with Zhong Ji REN-03 — four cun below the navel. It is one of the principal points for prolapse of the uterus, infertility, irregular menstruation and uterine bleeding.

The two characters are different (紫, purple, versus 子, child), the two points are at opposite ends of the trunk, and their uses do not overlap at all. Only the romanised spelling coincides. Because search engines and readers routinely conflate them, it is worth stating the practical rule: if the context is gynaecological, the point meant is almost always the abdominal extra point, not REN-19. Sacred Lotus holds both, on separate pages.

Is there research on REN-19 Zi Gong?

There is no point-specific clinical research on REN-19, and that should be said plainly rather than papered over. No randomised trial, no mechanistic study and no systematic review isolates this point. It appears occasionally as one component of multi-point chest protocols, and such trials measure the protocol rather than the point.

Two things do attach to it, and both are worth having:

• The anatomical literature is substantial and directly relevant — the sternal foramen work set out under needling (PMID 7723561, PMID 25023390, PMID 34280594, PMID 34053001, PMID 35385153). For a point on the breastbone, that anatomy is the most practically important research available.
• Searches for "Zigong" in the research literature return the other point. A search of PubMed for Zigong together with acupuncture returns gynaecological and fertility work — for example a 2026 data-mining analysis of acupoint selection across 220 acupuncture prescriptions for infertility (Int J Womens Health 2026;18:578082, PMID 41847472, PMC12990803, DOI 10.2147/IJWH.S578082) — and returns nothing for REN-19. This is a useful confirmation of the naming collision above: in the modern literature "Zigong" effectively means the abdominal extra point.

How does REN-19 compare with the points around it?

Shan Zhong REN-17, four rib spaces below on the same midline between the nipples, is the dominant point of this group — the front-mu point of the Pericardium, the Meeting Point of Qi, and the Sea of Qi point of the upper burner. Where a practitioner wants one chest point, it is almost always REN-17. Yu Tang REN-18 and Hua Gai REN-20 lie immediately below and above REN-19 and share its actions exactly; the three are effectively interchangeable, distinguished by level. Xuan Ji REN-21 sits on the manubrium above them. Tian Tu REN-22, in the suprasternal notch at the top of the breastbone, shares the descending-qi and throat actions but is a different proposition anatomically — it lies above the bone, not on it, and carries its own strong deep-needling caution. And Zi Gong Xue, the uterus extra point, is not a neighbour at all: it is on the lower abdomen, and shares only a spelling.

Source: Deadman & Al-Khafaji, A Manual of Acupuncture (p. 520); Chinese Acupuncture & Moxibustion (p. 240); Sacred Lotus sources & references (REN-19 record and the separate Zi Gong Xue extra-point record); PMID 41847472; sternal-foramen records cited under needling — each checked as active and not retracted; cross-referenced against multiple online sources.