Huan Zhong Round, Circle, Middle

What does Huan Zhong do?

Huan Zhong is an extra point in the buttock, belonging to no channel, so it carries no channel-theory actions — everything below comes from documented clinical use rather than from channel mechanics. In that documented use it does one thing: it is needled for pain in the lower back, hip and leg, and above all for pain that radiates from the buttock down the limb. Its recorded scope is narrow, local and entirely musculoskeletal.

• Used for lumbar and low back pain — the first documented use, and the one our own record names first.
• Used for pain of the hip and thigh — the region the point actually sits in, midway across the buttock.
• Used for pain radiating from the buttock down the leg — the sciatic-type presentation, and the reason the point exists as a named site distinct from its neighbours.
• Used for pain and weakness of the knee and lower leg — carried in the recorded use list as the radiating pain reaches further down the limb.
• Used as a local point in weakness and paralysis of the lower limb — recorded among the gluteal sites selected in the classical wei (flaccidity) presentations, as one point among several rather than alone.

Why does this page not say Huan Zhong "opens the channels and collaterals"?

Because Huan Zhong is on no channel, and a point that is on no channel cannot open one. The earlier description of this point opened with the claim that it "opens the channels and collaterals of the low back, hip and leg". That is channel-theory phrasing, and Huan Zhong has no channel and no five-shu, yuan, luo, xi-cleft, back-shu or front-mu classification — it was recorded for an observed clinical effect at a particular spot on the body, not derived from the channel system. What is documented is the clinical result: pain in the buttock and leg eases. The claim has been removed rather than quietly softened, and the reader is not left with less, because the point that genuinely carries that action lies a short distance away on the same line.

The channel point that carries the action is GB-30 Huan Tiao ("Jumping Round"), classified in Sacred Lotus sources & references as a Meeting Point of the Gall Bladder and Bladder channels and as one of the Ma Dan-yang Heavenly Star points. Its recorded actions are activating the channel and alleviating pain, benefiting the hip joint and leg, dispelling wind-damp, and reaching both the Gall Bladder and the Bladder channels at once — which is precisely the action being claimed above, held by the point that is entitled to it. On the other side, BL-54 Zhi Bian carries the Bladder channel through the buttock and DU-02 Yao Shu anchors the Governing Vessel at the sacral hiatus. Huan Zhong sits between GB-30 and DU-02, in the territory of both and belonging to neither. That is exactly what an extra point is.

Source: Sacred Lotus sources & references (existing use and action record, reframed as described — the broken list markup in that record corrected here; the absence of any channel or point-category classification for this point queried directly; GB-30, BL-54 and DU-02 records); Chinese Acupuncture & Moxibustion, extra points (p. 252); cross-referenced against multiple online sources.

What is Huan Zhong used for?

Huan Zhong is used for pain in the lower back, hip and leg, and for very little else. The indications carried in Sacred Lotus sources & references are lumbar pain and thigh pain, with the recorded use extending to hip and leg pain including sciatic-type radiating pain. The reference literature sets them out as follows. They describe traditional use, not proven treatment, and this point carries the safety facts set out under needling.

• Lumbar and low back pain
• Pain of the hip and buttock
• Pain of the thigh
• Pain radiating from the buttock down the back or outer side of the leg (sciatic-type pain)
• Pain and weakness of the knee and lower leg
• Restricted movement of the hip
• Numbness of the leg
• Weakness or atrophy of the lower limb, as a local point among others

Source: Sacred Lotus sources & references (existing indication and use record); Chinese Acupuncture & Moxibustion, extra points (p. 252); cross-referenced against multiple online sources.

How is Huan Zhong used in practice?

Huan Zhong lies deep in the buttock, on the line running from the great point of the hip across to the hollow at the base of the sacrum — our sourced location places it midway along that line, between Huan Tiao GB-30 on the outer side and Yao Shu DU-02 at the midline. It is a purely local point, treated on the affected side, and it is chosen for one reason: pain in the buttock, hip or leg that is not adequately reached from GB-30 alone. It is rarely used by itself, and a reader will rarely meet it outside a lumbar or sciatic prescription. Its modern extra-point designation in the back group is Ex-B12.

Which points is Huan Zhong combined with?

• With GB-30 Huan Tiao — the essential pairing, and the point Huan Zhong is defined in relation to. GB-30 is the great point of the hip and the whole lower limb, reaching both the Gall Bladder line down the outer leg and the Bladder line down the back of it; Huan Zhong is the companion site further along the same line towards the midline. Both are held in Sacred Lotus sources & references.
• With BL-54 Zhi Bian and BL-36 Cheng Fu — the Bladder-channel points of the buttock and upper thigh, used with it when the pain follows the back of the leg.
• With BL-40 Wei Zhong — the classical distal partner for the whole back and leg, behind the knee; BL-40 is one of the four Command Points, the one that commands the lumbar region.
• With GB-34 Yang Ling Quan — the Hui-Meeting point of the sinews below the knee, the standard distal partner when the pain follows the outer side of the leg.
• With the lumbar points — Shen Shu BL-23, and the extra points Yao Yan and Shi Qi Zhui Xia, added when the leg pain is traced to the lower back rather than to the hip. All are held here.
• With Ashi points — tender points found by palpation through the buttock, which in practice are what a gluteal prescription is usually built around.

Where does Huan Zhong sit among the extra points?

Sacred Lotus sources & references hold a group of extra points of the back and lumbar region alongside Huan Zhong: Hua Tuo Jia Ji, the paravertebral series running the length of the spine; Yao Yan ("Lumbar Eyes") in the hollows either side of the lower back; Shi Qi Zhui Xia ("Below the Seventeenth Vertebra") on the midline below the fifth lumbar vertebra; Yao Qi above the tip of the coccyx; and Pi Gen ("Tumour Root") beside the first lumbar vertebra. Among these Huan Zhong is the only one that sits out in the buttock rather than close to the spine, and the only one whose recorded use is specifically the radiating leg pain rather than the back itself. It also has a distant relative on the hand — Yao Tong Xue, the "Lumbar Pain Point", needled distally for acute lumbar sprain — which is the opposite strategy for the same complaint.

Source: Sacred Lotus sources & references (location record; the GB-30, DU-02, BL-54, BL-36, BL-40, GB-34, BL-23, Yao Yan, Shi Qi Zhui Xia, Hua Tuo Jia Ji, Yao Qi, Pi Gen and Yao Tong Xue records queried directly); Chinese Acupuncture & Moxibustion, extra points (p. 252); cross-referenced against multiple online sources.

Where is Huan Zhong located?

• Chinese Acupuncture and Moxibustion (p. 252): Midway between Huantiao (GB-30) and Yao Shu (DU-02)

How is Huan Zhong needled, and what lies beneath it?

The central safety fact must be stated before anything else: Huan Zhong is a deep gluteal point, recorded at 1.5 to 2 cun, sitting on the line between GB-30 Huan Tiao and DU-02 Yao Shu — the region through which the sciatic nerve and the gluteal vessels and nerves leave the pelvis. A point needled to two inches in a region occupied by the largest nerve in the human body is a point where contact with a nerve is an anatomical possibility rather than a remote one. Everything below is recorded as neutral reference data describing what the textbooks and the published anatomical studies 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 perpendicular insertion of 1.5 to 2 cun. For comparison, the figure held here for GB-21 at the shoulder is 0.3 to 0.5 inch and for REN-12 on the abdomen 0.5 to 1.2 inches; the neighbouring GB-30 is recorded at 1.5 to 2.5 inches. Huan Zhong therefore sits in the deep-needling class, at roughly four to five times the depth of a typical trunk point.
• Only one sourced depth figure exists for this point. Huan Zhong is not carried in Deadman & Al-Khafaji's A Manual of Acupuncture, which is why our location and needling records from that source are empty rather than incomplete. The depth above therefore rests on Chinese Acupuncture & Moxibustion and the wider reference literature alone, without the second independent record most points here have. Where a point has only one sourced figure, that should be known.
• The depth is bounded by muscle thickness, and muscle thickness varies enormously between people. Nothing in the gluteal region stops a needle short of the deep plane — there is no bone, membrane or fascial barrier between the skin and the layer the nerve occupies, only the bulk of the gluteal muscles.

The anatomy of the region

A needle in this part of the buttock passes through skin and subcutaneous fat, then gluteus maximus, then the deeper gluteal layer, and arrives in the plane occupied by the piriformis muscle and, immediately below piriformis, the sciatic nerve as it emerges from the greater sciatic foramen. The superior and inferior gluteal arteries, veins and nerves and the pudendal nerve pass through the same foramina. Huan Zhong lies medial to GB-30, along the line towards the sacrum, which places it nearer to where those structures leave the pelvis rather than further from them.

What has actually been measured — and on which point

The measured-anatomy studies below were carried out on GB-30 Huan Tiao and on the gluteal region in general. None of them measured Huan Zhong. They are recorded here because Huan Zhong lies on the same line, in the same tissue plane, at a comparable depth, and because measured figures from a neighbouring point are better reference than a vague warning — but the distinction must not be blurred, and no figure below should be read as a measurement of this point.

• Depth to the sciatic nerve has been measured, and it is highly variable. An ultrasound study of 50 volunteers aged 18–45 measured sciatic nerve depth in the gluteal region and the posterior thigh and built a prediction model from body measurements. The best single predictor was proximal thigh circumference, explaining 44.5 per cent of the variance; adding sex raised this to 49.7 per cent. The authors' stated purpose was to let clinicians estimate nerve depth in order to reduce the risk of accidental nerve injury during needle-based procedures (Minguez-Esteban I et al., J Clin Med 2024;13(24):7851, PMID 39768773). The finding that matters is the residual: roughly half the variation in how deep the nerve lies is not explained by body measurements at all. This study measured the gluteal region and posterior thigh, not a named acupuncture point.
• GB-30 has been reconstructed in three dimensions specifically to study needle safety. A Chinese study segmented the muscles, nerves and vessels around Huantiao GB-30 in a digitised human dataset and animated the insertion path through them, stating its objective as exploring the safety of needle insertion at that point (Zhongguo Zhen Jiu 2012;32(10):897–900, PMID 23259265). That a gluteal point should require a virtual-anatomy model to map its needle path is itself a statement about the region. The point modelled was GB-30, not Huan Zhong.
• No single agreed safe depth exists for any acupuncture point. Two systematic reviews of the safe-depth literature — 33 studies in the first, 47 in the second, measured by MRI, CT, ultrasound and cadaveric dissection — both concluded that depths measured for the same point differ greatly between subject groups and between measuring methods, and that "safe depth" has never been standardised (J Altern Complement Med 2011;17(3):199–206, PMID 21417806; Evid Based Complement Alternat Med 2013;2013:740508, PMID 23935678). Neither reports a figure for Huan Zhong, which is itself informative: this point has not been measured.

The nerve-injury signal

A sudden electric-shock sensation during needling is not a normal needling sensation. A review examined this directly, tracing the history of the recognised needling sensations, noting that the electric shock is included in some acupuncture sensation scales and excluded from others, and collating reported cases of acupuncture-related nerve injury in which the shock preceded the injury. Its conclusion is that the electric shock is caused by the needle entering a nerve directly, and that it should be treated as a warning sign of possible peripheral nerve injury rather than as a sign of correct technique (Guo Y et al., Neural Plast 2020;2020:8834573, PMID 33204248, PMC7655260). The distinction is genuinely contested in the literature — the propagated sensation down the leg that the reference texts describe as the response sought at deep gluteal points and a nerve-injuring contact are not easy to separate — which is precisely why it belongs on this page.

Risk in proportion. A meta-analysis of prospective clinical studies estimated serious adverse events across all acupuncture at approximately 1 per 10,000 patients and about 8 per million treatments, with roughly half of all recorded events being bleeding, pain or flare at the needle site (Bäumler P et al., BMJ Open 2021;11:e045961, PMID 34489268). A systematic review of the Chinese case-report literature from 1956 to 2010 identified 1,038 adverse-event cases across 167 articles and attributed them chiefly to improper technique, concluding that most were avoidable through standardised training (He W et al., J Altern Complement Med 2012;18(10):892–901, PMID 22967282). Serious harm at gluteal points is uncommon in absolute terms. The point is that where it does occur, the structure at risk is identifiable in advance.

Standard clean-needle practice applies. Acupuncture is carried out only by a qualified, licensed practitioner; this record documents the reference literature and is not a technique guide.

Source: Sacred Lotus sources & references (existing needling record; GB-30, GB-21 and REN-12 records for the comparison of recorded depths); Chinese Acupuncture & Moxibustion, extra points (p. 252); PubMed PMID 39768773, 23259265, 21417806, 23935678, 33204248, 34489268, 22967282 — each verified resolvable and checked as active and not retracted. The anatomical studies cited measured GB-30 Huan Tiao and the gluteal region generally; none measured Huan Zhong.

What does the name Huan Zhong mean?

Huan Zhong is rendered in Sacred Lotus sources & references as "Round, Circle, Middle" — huan meaning a ring, a circle or something round, and zhong meaning the middle. The name is best read as a positional one, and read that way it is entirely transparent. Huan is the same character that opens the name of its neighbour Huan Tiao GB-30 ("Jumping Round"), the great point of the hip; zhong places this point in the middle. Huan Zhong is, in effect, "the middle of the Huan Tiao line" — the site halfway along the line from Huan Tiao across to Yao Shu DU-02 at the base of the sacrum, which is exactly where our sourced location record places it. It belongs to a small family of extra points named by reference to the channel point beside them rather than by any image or function of their own: Bi Tong, also known as Shang Ying Xiang ("Upper Welcome Fragrance") after LI-20 Ying Xiang, is named the same way.

Is Huan Zhong a channel point?

No. Huan Zhong is an extra point (qi xue), carried in the back group with the designation Ex-B12. Extra points sit outside the fourteen channels: they were recorded for an observed clinical effect at a particular site rather than derived from channel theory, so they carry no five-shu, yuan, luo, xi-cleft, back-shu, front-mu, confluent or meeting classification. That is why our record shows no channel and no point categories, and why the actions above are framed as documented uses rather than as channel actions. Its neighbour GB-30 Huan Tiao is a channel point — a Meeting Point of the Gall Bladder and Bladder channels and a Ma Dan-yang Heavenly Star point — and that is the distinction to hold on to when reading the two records side by side. It is also why the two are not interchangeable: GB-30 is chosen for what it reaches, Huan Zhong for where it is.

How does Huan Zhong differ from the points around it?

GB-30 Huan Tiao lies laterally, at the junction of the outer third and inner two-thirds of the same line, and is by a wide margin the more important of the two — a meeting point of two channels, one of the twelve Ma Dan-yang Heavenly Star points held here, and the point the tradition reaches for first when pain runs from the buttock down the leg. BL-54 Zhi Bian lies medial to Huan Zhong, lateral to the midline at the sacral level, and carries the Bladder channel through the buttock. DU-02 Yao Shu sits on the midline itself at the sacral hiatus and anchors the Governing Vessel. GB-29 Ju Liao lies in front of GB-30 at the hip and is a meeting point with the Yang Motility vessel. Huan Zhong occupies the gap between the Gall Bladder point and the midline, and its whole justification is that it fills a gap the channel points leave — a very common reason for an extra point to exist, and a better one than it is usually given credit for.

Is there research on Huan Zhong?

The honest answer is that there is none. We searched the indexed biomedical literature directly for this point and found no clinical trial, no case series and no laboratory study of Huan Zhong, either alone or as a named component of a protocol. The single indexed record that matches the term is a Japanese history-of-medicine paper on the Cun Zhen Huan Zhong Tu, an eleventh- and twelfth-century Chinese anatomical and channel atlas (Nihon Ishigaku Zasshi 1996;42(1):77–86, PMID 11618879). That is a different huan zhong — the title of a book, not the name of this point — and it is recorded here only so that a reader who runs the same search knows what they have found. Every other apparent match is an author surname.

This is not a surprising result for a small, narrowly scoped extra point, and a short accurate record is better than a padded one. Two things follow and should be said clearly:

• The research that exists for this region is about GB-30 Huan Tiao, not about Huan Zhong. Where the safety section above cites measured anatomy, those studies measured GB-30 and the gluteal region generally. They are relevant to Huan Zhong because it lies on the same line in the same tissue plane, but they are not measurements of it, and this page does not present them as such.
• Trials of acupuncture for sciatica and lumbar pain do not name this point. The gluteal points that appear in that literature are GB-30, BL-54 and BL-40, together with Ashi points. Presenting whole-protocol sciatica trials as though they were evidence about Huan Zhong would be a misrepresentation, and none is presented here.

Huan Zhong's standing rests on the reference record and on continuous clinical use, not on trial evidence — and unlike most points on this site, it has not been studied at all.

Source: Sacred Lotus sources & references (extra-point status, location record, and the GB-30, GB-29, BL-54 and DU-02 records queried directly); Chinese Acupuncture & Moxibustion, extra points (p. 252); PubMed searched directly for this point, with no clinical or laboratory record found; PMID 11618879 (verified resolvable, not retracted — a history-of-medicine paper on a same-named classical atlas, not on this point); cross-referenced against multiple online sources.