中膂俞 Zhonglushu
“Central Spine Transport” · BL29
Foot Taiyang · 29 of 67
Where. On the sacrum, level with its third hollow, two finger-widths from the centre ridge.
For. Low back and sacral ache; loose stools.
Press. Reach behind and press with the fingertips, about a minute.
中膂俞，在第二十椎下，兩傍各一寸五分，俠脊胂而起按 · Press with me
Six slow breaths
About a minute. Press as you breathe out, ease as you breathe in.
鄰 · Neighbouring leaves
Where Zhonglushu Sits on the Sacrum
Zhonglushu takes its place at the very base of the back, where the spinal column finishes its long descent. The dataset locates it precisely: on the sacrum, 1.5 cun lateral to the median sacral crest, level with the third posterior sacral foramen. Unpacked for hands rather than rulers: the sacrum is the triangle of fused bone wedged between the hip bones below the waist, and its rear face shows a knobby ridge running down the middle — the median sacral crest. Flanking that ridge, four pairs of small openings pierce the bone; classical location counted them from above, and the third pair from the top sets this point’s level. Step outward from the crest by one and a half cun, and there, mirrored on both sides, sits Zhonglushu.
A cun is the traditional measuring unit of Chinese point-location: proportional lengths taken from the person being examined rather than from a ruler, so a cun across the pelvis of a broad-framed adult differs from a cun on a slight teenager. One practical rendering passed along through self-location teaching holds that the width of the index and middle fingers pressed together comes close to one and a half cun on many adult hands — helpful arithmetic, worth trusting only alongside the bony landmarks. The ground beneath the skin is honest here but thin: over the sacrum there is little muscle to cushion the touch, and skin, firm fascia, and bone lie close together under the fingertips. Nothing about finding this point asks for force; the landmarks announce themselves to patient, light contact. Why depth still deserves respect at this station is a matter the safety section takes up in full.
The neighborhood completes the map. The bladder meridian — the longest pathway in the body, sixty-seven stations strong, drawn in the old cartography from the inner corner of the eye, sweeping over the head, and descending the whole back to the little toe — travels down the spine in paired routes, the inner one running 1.5 cun from the midline. That inner road steps off the lumbar spine onto the sacral plate and keeps going, station by station: Xiaochangshu (BL27) level with the first posterior sacral foramen, Pangguangshu (BL28) with the second, Zhonglushu (BL29) with the third, Baihuanshu (BL30) with the fourth, while the paired liao points of the same channel take the foramina themselves as their addresses. Classical teaching read this stretch of road as the watch post over the lower belly, and assigned the whole channel to water, the phase tradition linked with storage and flow. A single foramen up or down changes the address; the third belongs to Zhonglushu.
A Self-Palpation Walkthrough
The low back is easy terrain to reach on yourself, so settle seated on a firm chair, spine tall but unforced, shoulders heavy. Begin by walking your fingertips down the centre seam of the low back: the lumbar knobs count downward one by one until, below the last of them, the discrete ridges give way to a smoother, flatter plate — that transition marks the top of the sacrum. Now slide down the plate’s midline ridge all the way to its end, where the knobby crest breaks into small bumps and finishes in a shallow notch just above the tailbone. From that notch, step outward one and a half cun — about two pressed-together finger widths — and begin walking gently upward along the side of the crest. The first soft depression your pad settles into belongs to the fourth-foramen level, the territory of BL30; continue one quiet step higher, and the next shallow hollow, level with the third posterior sacral foramen, is Zhonglushu. Repeat the whole search on the other side.
Confirmations cost nothing. Touch feather-light and compare sides: many people register a faint, dull awareness at the genuine spot and little sensation a thumb-width away. Check the horizontal position too: the true spot stays close beside the midline ridge, well inside the soft curve of the buttock — if your finger has wandered out toward the hip dimple, it has travelled several times too far. Lean on the neighbors as witnesses: whoever has located the notch at the sacrum’s foot can trust the count upward, and whoever finds BL30 can trust Zhonglushu one step above it. On some bodies the foramen depressions register only faintly through the covering tissues; when they do, hold the level rather than hunting for a dramatic hollow — the proportional distance from the crest and the counted position together carry more weight than any single sensation.
Four slips account for nearly every mislocation. Starting the count at the tailbone itself drops everything low — the search begins at the shallow notch where the midline ridge ends, not at the tailbone tip. Pressing on bare crest comes second; the point stands out to the side of the ridge, not on it. Drifting outward toward the fleshy buttock is third, and the correction never changes — return toward the midline. Forgetting the mirror pair is fourth — there are two Zhonglushu, and neither substitutes for the other. When doubt outlives every test, resist guessing from wherever the wandering ended: go back to the transition where the lumbar knobs give way to the smooth plate, walk down to the notch once more, and recount slowly from the bottom.
Reading the Name: Central Spine Transport
The characters tell the story in miniature. Zhong 中 means central or middle — the character even pictures a marker set through the middle of a field. Lü 膂 is the old word for the spine itself: traditional lexicography describes it as the bone of the spinal column, and the character survives today in the compound lüli 膂力, the strength of the back and body. Shu 俞 belongs to the family of characters used across the point catalogue for stations of transfer, carrying the sense of conveying or infusing, the way water passes along a channel from reach to reach. Together the name reads naturally as the central spine transport: a transfer station standing beside the body’s central column, right where the pillar of the spine settles into the pelvis. The tradition set an entire series of such addresses along the bladder channel’s inner road, and this one attends the stretch where the long descent ends.
That office explains the point’s historic company. In the traditional frame, the sacrum is the keystone where the spine’s column meets the frame of the pelvis, and the stations flanking the median sacral crest stood watch over the work of the lower abdomen — bowels and water alike. Classical lists accordingly gathered complaints of the intestines and of water metabolism around the lower reaches of the inner line, much as they gathered digestive matters around the transports of spleen and stomach higher up. The channel context deepens the picture: the tradition assigned the bladder meridian to water, the phase it linked with storing and flowing, and drew the channel’s route down the entire back before it passed the bladder’s own region and continued down the leg to the little toe. All of this is heritage cartography, offered warmly for understanding — a way the old texts organised the body, not anatomy confirmed.
Pinyin renders the name Zhōnglǚshū: zhong rides a flat, high first tone; lü dips through the third tone, falling and rising again, on a rounded ü vowel — shape the lips to say “oo” while aiming for “ee”; shu closes on another high first tone. The hanzi trio 中膂俞 stays legible at a glance once met — central, spine, transport — and like many points named for what they sit beside rather than what they do, the label performs real work. Gates imply thresholds; transports imply delivery; a spine-name plants this station firmly on the body’s central pillar. The name quietly states its instructions: whatever concerns the lower reach of the spine and the territory it shelters, this is where the tradition delivered its attention.
Traditional Indications, Explained
The recorded indications read: diarrhoea, hernia, lumbosacral pain, and difficult urination. The bowel entry leads the traditional telling. In the classical frame, diarrhoea was read as the intestines failing their sorting work — food and fluid arriving, but the clear and the turbid not being properly separated and sent where each belonged — so stations of the lower back served the low belly much as the digestive transports higher up served stomach and spleen. Hernia deserves slower reading: the old heading covered a family of troubles, including protrusions and colicky pains that descended toward the groin, and the sacral stations appear in those classical discussions. Today a hernia is understood as a structural problem, and honesty requires saying plainly what that means: a new lump in the groin or abdomen, or a known hernia that turns painful, red, or hard, calls for medical assessment promptly — never for pressing.
Difficult urination carried similar weight in the old records. Traditional teaching described trouble passing water — dribbling, weakness of stream, a bladder that would not release — as the qi of the lower region failing its transforming work, and the sacral stations stood among the addresses classical practice reached for in such discussions. Here too the modern translation must be made carefully: anyone who cannot pass urine at all, or who notices pain, blood, or fever alongside urinary trouble, needs prompt medical care, because these are signals to have assessed, never targets for pressure. Lumbosacral pain, the last recorded indication, looks least surprising of all: the point stands directly on the territory, where the spine meets the sacrum and so many low backs ache. Stations along a channel traditionally served the ground they traversed, and this one overlooks the very junction its own name describes.
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 context-dependent, and evidence specific to any single point remains thin. 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: seated, or lying with knees drawn up if that eases the low back, hands reaching comfortably behind. Curl the fingers and touch with the pads — never the tips — resting them on the spot either side of the spine’s base. 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 mild warmth, never sharpness. A common home rhythm is one to three minutes per side, once or twice daily, each circle riding a long exhale out; then swap hands and match the other side, keeping the two sessions symmetrical. Because both spots sit within easy reach, a slow figure-of-eight crossing the midline works too — lightness remains the whole discipline.
Quality outranks duration, as it does everywhere in gentle practice. Light, patient, regularly repeated contact is the entire method; jabbing against thin-covered bone teaches the body nothing and sours the experience. Warm cold hands first, because chilled muscle guards. Choose a quiet corner over a screen and let the session double as a pause — the base of the back absorbs more sitting hours than almost anywhere else and rarely receives deliberate attention. Readers who keep routines anchor this one somewhere natural: after the morning shower, before lights-out, or during the afternoon lull. Consistency, not intensity, is what self-care traditions actually ask for, here as everywhere.
Treat the exercise as a few minutes of attention paid to a stretch of yourself that cannot see itself. Across weeks you may notice the area feels less guarded, the low back easier while you press, or simply that you spent ninety seconds tending your own foundation — 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. Curiosity pulling that way should meet the same answer every time — return to gentleness, or stop for the day. The station is not going anywhere; tomorrow it will wait at the same third-foramen address.
Cautions and Safe Practice
The licensed record attaches no special caution to this particular entry, and absence of a warning should never be mistaken for license to press carelessly. The reason lives in the geography already described: over the sacrum, skin and firm tissue lie close to bone, and good practice anywhere near the spine favours exactly the habits gentle acupressure wants — patience, lightness, finger pads rather than force, and an early hand lifted from anything uncertain. Home self-care manages the risk completely by never leaving the surface at all. Feather-light fingertip work engages skin and superficial tissue alone, which is the whole intention of this page.
For fingertip practice the rules follow plainly. Keep contact light and strictly superficial — the intention stays at the surface, never driving inward toward bone or toward the groin. Use finger pads, never elbows, knuckles, tools, or devices. Skip the point entirely during feverish illness or any acute flare, and over broken, irritated, or inflamed skin. Never press over a known or suspected hernia. After recent low-back, pelvic, or abdominal surgery or injury, wait until a clinician clears ordinary activity. Sharp, electric, or radiating sensation means stop at once, and not again that day. Pregnant readers, and anyone living with ongoing bowel, bladder, or spinal conditions, should consult a qualified practitioner before adding any new point practice. And when energy runs low or unwellness visits, the wisest session is the postponed one — rest is also self-care.
Over everything stands the wider rule: this page is educational, and acupressure is self-care, not diagnosis or therapy. Seek prompt medical care — not a longer pressing session — for blood in the stool, diarrhoea that stretches on or arrives with fever, a new lump in the groin or abdomen, inability to pass urine, or severe low-back pain accompanied by numbness, leg weakness, or any loss of control over bladder or bowels. Persistent complaints belong with a licensed practitioner, medical or East Asian medical as suits the problem. The image of a quiet transport station at the foot of the spine is elegant, and it earns its keep as memory and meaning; but the safest gift Zhonglushu offers most people is a calmer acquaintance with their own low back, tended lightly and surrendered promptly whenever the body asks for more than gentleness can give.
Zhonglushu, the Central Spine Transport, rests on the back of the sacrum, a thumb-and-a-half out from the midline, level with the third pair of small openings in the triangular bone at the base of the spine. Classical practice reached for this quiet station when bowels, passing water, or the low back itself complained. This guide walks through finding it by touch and pressing it gently.
Self-care limits
Frequently asked
- How do I find Zhonglushu without knowing anything about cun?
- Use the sacrum’s own outline as the map. Walk down the centre seam of the low back until the knobby lumbar ridges give way to the smoother triangular plate; follow the plate’s midline ridge to its end at a shallow notch above the tailbone; step out two pressed-together finger widths; then count the soft depressions upward — the second hollow you meet, level with the third posterior sacral foramen, is the address. Cun measurements simply encode the same landmark sequence in proportional language.
- Is pressing Zhonglushu myself actually safe?
- Gentle fingertip pressure held on the surface is generally reasonable self-care for healthy adults; the licensed record attaches no special caution to this entry. But no caution never means license for force: the bone lies close beneath thin coverings here, so keep contact light, superficial, and pad-only, and skip the point over irritated skin, during feverish illness, or over any known or suspected hernia. Sharp pain, radiating sensation, or discomfort that worsens means finish immediately.
- What did classical practice use Zhonglushu for?
- The traditional record lists diarrhoea, hernia-type complaints, lumbosacral pain, and difficult urination. As a station of the bladder channel’s inner line beside the sacral crest, it joined the classical discussions of the low belly’s work — bowels and water — and of the junction where spine meets sacrum. Those are traditional frameworks for understanding the body, documented for context — not evidence-backed treatment claims.
- Why does a point for the low belly sit on the sacrum?
- Classical cartography draws the bladder meridian descending the entire back in paired routes, and the inner line — 1.5 cun from the midline — continues off the lumbar spine onto the sacral plate, carrying stations the tradition matched to the territory below. Water, the channel’s assigned phase, is the element of storage and flow, and the sacral stations stood watch over exactly that work. Bilateral symmetry doubles everything: there is a Zhonglushu on each side of the crest.
- Can acupressure at Zhonglushu replace seeing a doctor about my symptoms?
- No. Self-acupressure is a comfort practice, not a diagnostic tool. Blood in the stool, persistent or bloody diarrhoea, a new lump in the groin, inability to pass urine, or severe back pain with numbness or weakness call for professional assessment promptly — think of daily self-care and clinical medicine as caretakers of two different doors, each minding its own threshold, neither substituting 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, sacral-station context, and bladder-channel background.
- 03aijiu-mpvue (MIT License) licensed dataset, entry for BL29 Zhonglushu — location, point class, actions, and caution 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/bl29/leaf.json
- GET /zh-hant/points/bl29/leaf.json
- GET /zh-cn/points/bl29/leaf.json
- /llms.txt — the index of every leaf
- JSON-LD in the page: MedicalWebPage, MedicalEntity and FAQPage
{
"id": "BL29",
"name": {
"en": "Zhonglushu",
"gloss": "Central Spine Transport",
"zh-Hant": "中膂俞",
"zh-Hans": "中膂俞"
},
"channel": {
"id": "BL",
"order": 29,
"of": 67
},
"location": {
"text": "On the sacrum, level with its third hollow, two finger-widths from the centre ridge."
},
"for": [
"low back and sacral ache",
"loose stools"
],
"press": {
"text": "Reach behind and press with the fingertips, about a minute.",
"seconds": 60
},
"cautions": [],
"source": "Zhenjiu Jiayi Jing, book 3",
"url": "https://acupoints.com/en/points/bl29",
"lastReviewed": "2026-08-25"
}