Ciliao

What is BL32?

BL32 (Ciliao) is a Bladder channel point over the second small hollow in the sacrum, the flat bone at the base of the spine.

It is one of a row of four sacral points (BL31 to BL34) that every acupuncture curriculum teaches and the classical texts list. In traditional terms, BL32 is linked to the lower abdomen and pelvis, and is used for period pain, lower back ache and urinary complaints. That long history tells you the point is well known. It does not tell you the point works, and it does not tell you the point is safe for you.

Here is the honest verdict on the evidence. Sacral points including BL32 have been studied in people, but nearly all of that work used needles or needles with electrical stimulation, not finger pressure. Self-applied acupressure at BL32 has very little direct testing, and the few studies that exist are small, short and hard to blind. So the fair summary is: plausible for comfort, unproven for outcomes.

This page is about self-applied finger pressure only. Nothing here involves needles, skin-breaking or heat therapy, and none of it replaces care from a doctor or midwife.

One instruction comes before everything else on this page. Do not press BL32 if you are pregnant or think you might be. BL32 is on every teaching tradition's list of points to avoid in pregnancy. It is sometimes used around labour, but that is a decision for a midwife or doctor who knows your pregnancy, never a decision you make from a video or from this page.

Read the location section before you press anything. The sacrum is bony, and most people land on bone rather than in the hollow the tradition actually describes.

Where is BL32 and how do you find it?

BL32 sits in the second small dip in the sacrum, just inside and below the bony bumps either side of your lower spine.

• Find the two dimples first. Run your hands down your lower back to the top of your buttocks. Most people have two shallow dimples there, one on each side, sitting over a bony knob called the posterior superior iliac spine.
• Find the midline ridge. Between and below those dimples is the sacrum, a broad triangular bone. Its centre line feels like a firm ridge running down towards the tailbone.
• Move in and down. From the dimple, slide your thumb towards the midline and slightly downwards. You are aiming for a point about one thumb-width (roughly 2 cm) out from the centre ridge.
• Feel for softness. BL32 is in a small give or hollow in the bone, not on the hard ridge. Under firm pressure it often feels slightly tender or spreads a dull ache into the buttock.
• Check the level. BL32 is the second of four hollows going down. The first (BL31) is roughly level with the dimples, and BL32 is a finger-width or so below it.
• Work both sides. The point is paired, one on the left and one on the right of the midline.

If you cannot feel a distinct hollow, that is normal. Sacral anatomy varies, and body fat and muscle cover the area. Press the general zone one thumb-width out from the midline, a finger-width below the dimple line, rather than hunting for a perfect spot.

Reaching behind your own back is awkward. Many people find the area more easily lying on their back with a knuckle or a soft ball under the sacrum, letting body weight do the work.

How do you apply pressure to BL32?

1. Get in position. Stand and reach behind you with both thumbs, or lie on your back with a knuckle or a soft ball placed under one side of the sacrum. Lying down is easier on the shoulders.
2. Settle on the spot. Place your thumb pad in the dip about one thumb-width out from the midline ridge, a finger-width below the dimple. Keep off the hard central ridge.
3. Press slowly. Lean in over about five seconds until the pressure feels firm and slightly tender, roughly a four to six out of ten. It should never feel sharp or electric.
4. Hold and breathe. Keep steady pressure for 30 to 60 seconds, breathing out slowly. Small circles the size of a coin are fine if that feels better than a static hold.
5. Release and repeat. Ease off over a few seconds. Do two or three rounds per side, then swap sides so both are treated.
6. Keep it short. Three to five minutes in total, up to two or three times a day, is plenty. More pressure is not better, and longer is not better.
7. Stop when told to. Stop at once if you feel sharp pain, shooting pain down a leg, pins and needles, numbness, or if the skin breaks or bruises.

Use fingers, thumbs or knuckles only. Do not use anything sharp, and do not have someone stand or kneel on your sacrum.

Mild local tenderness for an hour or two afterwards is common and usually settles. Pain that is worse the next day means you pressed too hard, so give the area several days off.

If you are using this for period pain, warmth over the lower back before or after pressing is a reasonable comfort measure, and it is something people often find more useful than harder pressing.

What is BL32 traditionally used for?

• Period pain. Tradition treats the sacral points as the main local area for menstrual cramping. Human trials of acupuncture for period pain exist, and some report reduced pain, but they are mostly small, often unblinded, and usually test needles rather than finger pressure. Treat BL32 as possible short-term comfort, not treatment.
• Low back and sacral ache. BL32 lies in the muscle and ligament region that commonly aches in non-specific low back pain. Firm pressure here often feels good, and pressure or massage over tender back areas has modest short-term evidence in general. Evidence for BL32 specifically is weak.
• Bladder symptoms and urinary leaking. Classical use links the sacral points to the bladder. Research on this has used needling with electrical stimulation at sacral points in women with stress urinary incontinence, with some benefit reported. That tells you little about pressing with a thumb at home.
• Sciatica-type leg pain. The point is traditionally used when ache spreads from the lower back into the buttock. Direct trial evidence for BL32 here is essentially absent, and leg pain with numbness or weakness needs a doctor rather than pressure.
• Labour pain. Sacral pressure is used by some midwives during labour, and small studies of sacral acupressure in labour report lower reported pain scores. This is not something to start yourself. A midwife or doctor decides whether, when and how it is used in your labour.
• Pelvic heaviness and lower abdominal discomfort. A long-standing traditional use with no useful human trial evidence behind it for this point.

Across all of these, the pattern is the same. Tradition is consistent and detailed, human evidence is thin, and almost none of it tests the thing you would actually do at home.

Are there tips for using BL32 effectively?

• Do not use it in pregnancy. Do not press BL32 if you are pregnant or think you might be. Every teaching tradition puts this point on the avoid list for pregnancy, and the sensible response to that is to leave it alone and choose a different approach.
• Let a professional decide about labour. If you have heard about sacral pressure in labour, raise it with your midwife or doctor in advance. They decide whether it is appropriate for you, and when.
• Lie down instead of reaching. Placing a soft ball or a folded towel under the sacrum and letting your body weight press is far easier than twisting your arms behind your back.
• Warm the area first. A warm shower or a heat pack for a few minutes makes the tissue more comfortable to press, especially with period pain.
• Stay off the midline. The hard centre ridge and the tailbone are not the point. Work one thumb-width to either side, where the bone gives slightly.
• Match pressure to tenderness. A dull ache you can breathe through is the target. Pain that makes you hold your breath is too much.
• Give it a fair trial, then judge. Try it over a week or two and note whether anything changes. If nothing shifts, stop rather than pressing harder.
• Keep your other treatment going. Acupressure is an add-on. Do not drop prescribed painkillers, bladder treatment or physiotherapy because you have started pressing a point.
• Check your skin. Look at the area afterwards. Redness that fades is fine; bruising means you were too heavy-handed.

What do people get wrong with BL32?

• Using it while pregnant. Do not press BL32 if you are pregnant or think you might be. This is the single most common and most important mistake with this point, and a video that omits it is not a reliable guide.
• Expecting a cure. No acupressure point cures period pain, back pain or bladder problems. At best BL32 may offer some short-term comfort for some people. Going in expecting more leads to disappointment and to delayed medical care.
• Pressing on bone. Landing on the hard central ridge of the sacrum instead of the small hollow a thumb-width to the side. It hurts, it does nothing, and it bruises.
• Confusing it with its neighbours. BL32 is the second of four sacral hollows. People often press BL31 (higher, level with the dimples) or BL33 (lower) by mistake. Being a finger-width out is not a disaster, but know which one you are aiming for.
• Going too hard. Grinding a knuckle in for several minutes leaves bruising and sore ligaments. Firm and brief beats hard and long.
• Pressing damaged tissue. Working over broken skin, a rash, a fresh bruise, a recent tailbone or sacral fracture, or an area that has just had surgery. Leave those alone completely.
• Ignoring warning signs. Treating numbness around the groin, leg weakness or new loss of bladder or bowel control as something to press out. Those need urgent medical assessment, not acupressure.
• Copying needling videos. Clips showing needles or heat therapy at this point are showing practitioner procedures. Nothing on this page involves breaking the skin.

What does the research on BL32 actually say?

There is real human research involving the sacral points, but very little of it tests what this page describes, which is pressing with a thumb.

The largest body of work used needles, often with electrical stimulation, over the sacral area in women with stress urinary incontinence (leaking urine on coughing or exercise). A large randomised trial in China reported modest reductions in leakage compared with a sham procedure. That is a practitioner-delivered procedure under clinical supervision, and its results cannot be read across to finger pressure at home.

For period pain, several small randomised trials and reviews have looked at acupuncture and acupressure, sometimes including sacral points. Some report lower pain scores over a cycle or two. The trials are generally small, participants usually know what they received, and the quality of the reviews is often rated low. Reviewers tend to conclude that an effect is possible but not established.

For labour, a few small studies of sacral acupressure applied by trained staff report lower reported pain during contractions. These are small, unblinded, and the comfort of touch and attention is hard to separate from the specific point. They also describe care delivered by a midwife or clinician, not self-care.

For BL32 alone, as self-applied acupressure, no high-quality human trial is available. Points are nearly always used in combinations, so even positive studies rarely tell you what any single point contributed.

What that means in practice: if pressing BL32 is comfortable and you are not in any of the avoid groups, it is a low-cost thing to try. It is not a substitute for assessment of heavy or worsening periods, persistent back pain, or urinary symptoms.