Not in pregnancy, or if you could be pregnant.
中髎 Zhongliao
“The Middle Bone-Hole” · BL33
Foot Taiyang · 33 of 67
Where. In the third small hollow on the sacrum, a little below and inside BL32.
For. Irregular periods; constipation; low back ache.
Press. Reach behind and press with the fingertips, about a minute.
Caution. Not in pregnancy, or if you could be pregnant.
中窌，在第三空，俠脊陷者中按 · Press with me
Six slow breaths
About a minute. Press as you breathe out, ease as you breathe in.
鄰 · Neighbouring leaves
Where Zhongliao Sits on the Sacrum
The sacrum is the strong triangular bone at the back of the pelvis — the plate into which the five lumbar vertebrae of the small of the back slot from above, and which tapers downward to end at the tailbone. Run a hand down the spine and you can feel the change of country: bony ridges give way to a smoother, flatter expanse that widens at the hips and narrows toward its lower tip. On this plate the dataset places Zhongliao below and medial to Ciliao (BL32), exactly over the third posterior sacral foramen. Unpacked: the fused sacral bone carries four pairs of small openings on its back surface, one pair beneath the other, and the third of these from the top is the address recorded here. Medial means toward the body’s central seam; because the sacrum narrows as it descends, each lower opening sits a shade closer to that seam than the one above it — which is why the record describes Zhongliao not merely as below its neighbor but also inward of it.
The terrain under the fingertips is friendlier than most of what the back offers. Along the sacrum’s midline runs a ridge of small, closely spaced bony bumps, easily traced through the skin; flanking it on either side lies a shallow groove, and set along each groove are gentle depressions marking the openings beneath. Over everything lies generous padding — the muscles of the low back flowing into the buttock — and beneath the padding lies bone fused into a single solid piece. Nothing delicate rides close to the surface here: no thin-walled cavity behind a narrow gap, no vessel or organ within reach of unhurried fingertip contact. Like nearly every station on the trunk, the point exists twice, mirrored left and right of the seam, and the two sides reward being located and treated as a pair.
The neighborhood explains the name’s whole family. Descending the sacrum come four paired stations of the bladder channel: Shangliao (BL31), the upper pair; Ciliao (BL32), the second pair; Zhongliao itself; and Xialiao (BL34), the lower pair, whose record notes it stands beside the sacral hiatus — the opening at the sacrum’s lower end, just above the tailbone. Together the eight are spoken of as one group in classical literature, and the ladder they form runs upper, second, middle, lower. They stand on the territory of the body’s longest channel: the bladder meridian, drawn in the old cartography from the inner corner of the eye, sweeping over the head, and descending the entire back to the little toe, sixty-seven stations strong. On the sacrum its route continues in mirrored pairs beside the midline, and the pairing carries a quiet aptness — kidney and bladder are the two water-element channels of classical teaching, host and guest drawing on the same element.
A Self-Palpation Walkthrough
Choose a position that lets the low back soften: lying face down with a pillow under the ankles, or standing with weight even on both feet and the hips released. First find the country you are in. Rest a palm on the small of the back and slide downward past the last prominent spinal ridge onto the smoother plate of the sacrum; keep going until the plate ends and the tailbone begins. Trace the midline ridge of small bumps from top to bottom of the plate once, slowly, so your fingers know its length. Then park your fingertips in the soft ground immediately beside the ridge — not on the bumps themselves but on the shallows flanking them — and let the searching hand work there.
Two routes lead to the same spot, and using both turns guessing into confirmation. Counting upward from the bottom: starting at the tailbone, walk your fingertips up the groove beside the ridge. The first gentle depression you meet on either side belongs to the neighborhood of Xialiao, the lowest station; continue upward and the next depression is Zhongliao’s, the third opening’s territory. Counting downward from the top: many people carry a pair of shallow dimples just above the sacrum’s broad upper corners; beginning near that region and walking down the groove, the depressions arrive in order, and Zhongliao is the third. Before any pressure begins, touch feather-light and compare sides: most people notice a faint, dull awareness at the true spot and little sensation a finger-width away, and the mirror test helps too — whatever hollow your finger found on one side should have a twin at the same height on the other.
The usual slips deserve naming. The first is settling on the central ridge itself instead of the depressions beside it; the ridge is landmark, not destination. The second is drifting outward toward the hip, where the sacrum gives way to softer tissue and sensation goes mute. The third is losing count among depressions that sit close together — fingers skip, especially upward. Whenever doubt arises, return to the tailbone and climb again, slowly, letting the bottom-up count confirm the top-down one. And remember the point is a small zone rather than a pinhead: patient searching within half a thumb-width finds it faster than force ever could. Whatever you locate on one side, repeat faithfully on the other; paired stations forgive small errors but reward symmetry.
Reading the Name: the Middle Bone-Hole
The characters tell the story plainly. Zhong 中 means middle or central — the ancient form pictures a marker set through the centre of a field. Liao 髎 carries the bone radical and names a hollow in bone: dictionaries gloss it as the gaps or openings among bones, and every point bearing the character lives in exactly such geography, seated at a bony hole, notch, or seam. Joined, the name reads the middle bone-hole, and the reading is literal before it is poetic: Zhongliao occupies the middle station among the sacral openings. The four pairs were named as addresses on a ladder — upper, second, middle, lower — descending the same plate of bone, so the name does double duty as description and as street number. Reading it, you already know where the point sits relative to its siblings.
Classical texts describe openings in bone as favoured doorways — places where a channel’s activity passes closest to the surface and can be met with the least intervening tissue. On the sacrum the imagery gathers extra force, because the sacrum was understood as the root of the spine’s back, the base from which the trunk meets the lower limbs, and because the governing vessel climbs the body’s very centre while the bladder channel’s stations flank it on either side. Classical literature discusses the eight liao together, as a row of doors attending to the pelvis’s business — the waters, the bowels, the womb, and the frame that carries them — with Zhongliao holding the middle office. None of this requires embellishment: the tradition’s own naming and grouping do the explaining, handed down without quotation marks needed.
Pinyin renders the name Zhōngliáo, and the tones repay attention. The first syllable, zhong, carries the high, level first tone — held flat, like a sustained note. The second syllable, liao, carries the rising second tone, climbing upward from middle pitch to high. Say them in sequence and the name rises gently at its end — fittingly, perhaps, for a station found by climbing the sacrum from below. The hanzi pair 中髎 stays short enough to memorise at a glance. Like so many stations across the body’s maps — gates, valleys, courtyards, storehouses — the metaphor here does real work: it tells you the tradition treats this spot as a doorway in bone, a place of passage, not scenery. The name is itself a small set of instructions.
Traditional Indications, Explained
The recorded actions read: irregular menstruation, vaginal discharge, difficult urination, constipation, diarrhoea, and lumbosacral pain. Framed as tradition rather than promise, the list gathers itself around the pelvis’s daily business, and the sacral stations were classically treated as a family attending to it. The first two entries concern the womb’s cycle. Irregular menstruation covered cycles arriving early, late, or out of their accustomed rhythm; vaginal discharge named the normal secretions gone awry in amount, colour, or accompaniment. Classical medicine discussed these matters openly and matter-of-factly, as ordinary concerns of women’s health belonging to ordinary channels of care — and they deserve equally unembarrassed mention today.
Then come the waters and the bowels. Difficult urination — hesitancy, straining, the sense of incomplete emptying — belonged naturally to the bladder channel’s portfolio, since the channel bears the organ’s name and the tradition made the bladder governor of the surface waters, in partnership with the kidney that holds the deep reserve. Constipation and diarrhoea appear side by side in the same record, which looks contradictory until the traditional reading is restored: sacral stations were approached for regulation rather than propulsion in either direction — helping what was stuck to move and what was loose to gather, according to what the person presented. Last comes the plainly local entry: lumbosacral pain. The point sits precisely where the low back hands over to the pelvis, so aches settling into that junction — from strain, posture, or the wear of carrying — were approached at stations along the route, and the middle of the liao row stood ready among them.
It bears repeating plainly: these are the traditional uses recorded in a licensed dataset and classical literature, offered here for cultural and historical understanding. They are not claims that pressing this point treats disease, and nothing in this guide replaces assessment by a qualified clinician. Where modern research touches self-applied pressure at all, reviews suggest effects are modest and dependent on context, and evidence specific to any single point remains thin. Menstrual, urinary, and bowel symptoms in particular have long lists of possible stories behind them, several of which want professional eyes first. Hold the tradition lightly, and hold the safety rules firmly.
Self-Care Acupressure at Home
With the point located by the walkthrough above, settle into position. Standing works well here — the sacrum sits within easy reach — so let the hands pass behind the back and rest the pads of the thumbs, or of two fingers, on the two spots at once; lying face down suits the practice equally. Begin with contact alone for a few slow breaths, then add small, unhurried circles, letting the skin glide over the firm ground beneath rather than grinding against bone. Pressure should register as pleasant dullness or spreading warmth, never sharpness. A common home rhythm is one to three minutes at a time, once or twice daily, matched where possible to long exhales so each circle rides the breath out. Keep the two sides symmetrical — what one receives, the other should too.
Quality matters more than duration. Warm your hands first if they run cold, because chilled muscle guards. Choose a quiet corner over a screen and treat the few minutes as a pause rather than a task; people who keep the habit often anchor it to something existing — after the evening wash-up, before bed — because consistency, not intensity, is what self-care traditions actually ask for. What follows the pressing matters too: a minute of gentle contact pairs well with easy movement afterward — lying down and drawing both knees toward the chest, rocking softly, or simply walking unhurriedly around the room — far better than aggressive stretching of freshly worked tissue. What the sacral region asks of self-care, more than anything, is patience and regularity; hard jabbing teaches the body nothing except to brace.
Treat the exercise as a small ceremony of attention rather than a treatment session. Across weeks, notice what changes: perhaps the area feels less guarded, perhaps the low back carries the day more easily, perhaps nothing shifts except that you spend two minutes attending to a part of the body most people never think about until it complains. Every one of those outcomes fits the honest scope of self-acupressure. What does not fit is escalation — pressing harder, longer, or deeper to force a result, or continuing through pain out of stubbornness. When curiosity pulls that way, return to gentleness or simply stop for the day; the doorway will still be there tomorrow, exactly where the tailbone and the counted depressions said it would be.
Cautions and Safe Practice
This point carries a notably quiet record in the licensed data: the dataset lists no specific caution for Zhongliao. Geography explains much of that calm. Beneath the skin lie well-padded muscle and bone fused into one solid piece; nothing fragile lies close to the surface the way it does behind the ribs or at the throat, and professional technique at this site faces fewer anatomical hazards than at many exacting stations higher on the trunk. But a quiet record is not a license for force. The point stands on the body’s central pillar, close beside the seam where spine meets sacrum, and respect scales with proximity: home care never leaves the surface, and gentleness remains the whole craft.
For fingertip acupressure the practical rules are simple. Use finger pads only — never elbows, knuckles, or tools — and keep pressure light enough to stay pleasant throughout. Skip the point entirely over broken, bruised, or irritated skin, during an acute flare of back trouble, and for a stretch after any recent injury or surgery in the region, until ordinary movement has been cleared by a clinician. Sharp, electric, or radiating sensation means stop at once and do not try again that day. Pregnant readers should consult a qualified practitioner before adding any new point practice — counsel worth double weight here, given how closely the sacral stations were tied to matters of the womb in the old records. Anyone living with osteoporosis or a diagnosed condition of the bones of the spine or pelvis does well to ask first as well — not because gentle surface contact is known to harm, but because individual circumstances deserve individual advice.
And the wider rule stands over everything: this page is educational, and acupressure is self-care, not diagnosis or therapy. Some stories need prompt professional attention rather than any pressure routine: urinary symptoms accompanied by fever; blood in the urine or stool; sudden changes in bladder or bowel control; severe or rapidly worsening pelvic or low-back pain; bleeding that alarms you. Seek licensed medical or East Asian medical care as suits the complaint — promptly, and alongside self-care rather than instead of it — and bring persistent symptoms of any kind, menstrual, urinary, or otherwise, to a practitioner rather than waiting them out alone. The doorway imagery is elegant, but the safest gift Zhongliao offers most people is a better acquaintance with their own sacrum: attended kindly, pressed lightly, and referred onward whenever the body raises its voice.
Zhongliao, the Middle Bone-Hole, sits low on the sacrum, third of the four paired stations tradition calls the eight liao. Classical practice reached for this quiet family when menses ran irregular, discharge troubled, water passed with difficulty, bowels bound or loosened, or the low back and sacrum ached. This guide walks through finding it by touch and pressing it gently at home.
Self-care limits
Frequently asked
- How do I find Zhongliao without knowing anything about sacral foramina?
- Use the tailbone as your map. Find the sacrum — the smooth plate below the small of the back, ending at the tailbone — and locate the midline ridge of small bumps running down it. Starting at the tailbone, walk your fingertips up the shallow groove beside that ridge: the first gentle depression you meet belongs to the lowest station, Xialiao, and the next depression up is Zhongliao’s neighborhood, over the third opening. Cross-check by counting down from the shallow dimples many people carry above the sacrum’s upper corners. Light touch and comparing the two sides will confirm the spot better than any diagram.
- Is pressing Zhongliao myself actually safe?
- For healthy adults, gentle fingertip pressure held on the surface is generally reasonable self-care here: the area is padded with muscle over bone fused into one solid piece, and nothing delicate lies close beneath the skin — the licensed record reflects that, listing no specific caution for this point. Safety is mostly restraint and judgment: light force, finger pads only, healthy skin only, an immediate stop if anything feels sharp or radiating, and a practitioner consulted first during pregnancy or with diagnosed bone conditions.
- What did classical practice use Zhongliao for?
- The traditional record lists irregular menstruation, vaginal discharge, difficult urination, constipation, diarrhoea, and lumbosacral pain. Classical literature treats the eight liao as a family of sacral stations gathered around the pelvis’s affairs — the cycle, the waters, the bowels, and the frame — with Zhongliao holding the middle post. Those are traditional frameworks for understanding the body, documented for cultural context — not evidence-backed treatment claims.
- Why are there four pairs of liao, and what makes this one middle?
- Because the sacrum carries four pairs of openings on its back surface, and the tradition gave each pair an address on a descending ladder: Shangliao the upper pair, Ciliao the second, Zhongliao the middle, Xialiao the lower — upper, second, middle, lower, top to bottom of one plate of bone. Zhongliao’s name is therefore both description and street number: the middle bone-hole among them, seated neither highest nor lowest but squarely between.
- Can acupressure at Zhongliao replace seeing someone about my cycle or urinary trouble?
- No. Self-acupressure is a comfort practice, not a diagnostic tool, and menstrual, urinary, and bowel symptoms each carry lists of warning signs — fever, blood, sudden changes in control, severe or worsening pain — that call for prompt professional assessment rather than a pressure routine. Think of the two as different floors of the same building: daily self-care lives downstairs, and clinical medicine keeps the consulting room upstairs that you visit when symptoms persist, escalate, or frighten you. Neither substitutes for the other.
Sources
- 01WHO Standard Acupuncture Point Locations in the Western Pacific Region (2008), World Health Organization — nomenclature conventions.
- 02A Manual of Acupuncture, Peter Deadman, Mazin Al-Khafaji and Kevin Baker — point-name tradition, the eight-liao series, and channel context.
- 03aijiu-mpvue (MIT License) licensed dataset, entry for BL33 Zhongliao — location, point class, actions, and indication record.
Last reviewed
牌記This leaf, for machines
Old books ended with a colophon saying who printed them. Every leaf here carries the same facts as structured data for agents and search, with no layout in the way.
- GET /en/points/bl33/leaf.json
- GET /zh-hant/points/bl33/leaf.json
- GET /zh-cn/points/bl33/leaf.json
- /llms.txt — the index of every leaf
- JSON-LD in the page: MedicalWebPage, MedicalEntity and FAQPage
{
"id": "BL33",
"name": {
"en": "Zhongliao",
"gloss": "The Middle Bone-Hole",
"zh-Hant": "中髎",
"zh-Hans": "中髎"
},
"channel": {
"id": "BL",
"order": 33,
"of": 67
},
"location": {
"text": "In the third small hollow on the sacrum, a little below and inside BL32."
},
"for": [
"irregular periods",
"constipation",
"low back ache"
],
"press": {
"text": "Reach behind and press with the fingertips, about a minute.",
"seconds": 60
},
"cautions": [
"Not in pregnancy, or if you could be pregnant."
],
"source": "Zhenjiu Jiayi Jing, book 3",
"url": "https://acupoints.com/en/points/bl33",
"lastReviewed": "2026-08-25"
}