Sidu

What is TE9?

TE9 (Sidu) is a point on the back of the forearm, about a third of the way down from the tip of the elbow towards the wrist.

Its Chinese name, Sidu, is usually translated as "four rivers" or "four ditches", a reference to the grooves and channels of the forearm. It belongs to the Triple Energizer channel, which runs from the ring finger, up the back of the arm, over the shoulder and round the ear.

In classical texts TE9 is a minor but standard point. It is listed in the main point manuals and taught in every acupuncture curriculum, yet it is rarely a headline point. Traditional writers linked it to the ear, the throat and the voice, to toothache, and to pain in the arm itself.

Here is the honest verdict on the evidence: there is essentially no human research on TE9 specifically. Nothing has been tested on this point for hearing, voice, teeth or headache in a way that would let anyone promise a result. Most of what you will read online about Sidu is tradition restated with confidence it has not earned.

Two things are worth stating plainly, and this page will not repeat them in every section. First, a long traditional record is not evidence that a point works; people have believed useful-sounding things for centuries without testing them. Second, a long traditional record is not evidence that a point is safe either. Safety has to be judged from what is under your fingers — in this case forearm muscle, two bones, and nerves and vessels running between them.

What acupressure on TE9 can reasonably offer is what any gentle self-massage of a tired forearm offers: a few minutes of attention, slow breathing, and some local easing of tight muscle. That is a modest and real thing. Treat anything grander as unproven.

Where is TE9 and how do you find it?

TE9 sits on the back of the forearm, in the furrow between the two forearm bones, roughly 5 thumb-widths below the bony tip of the elbow.

• Start with the palm down. Rest your forearm on a table or your thigh with the back of the hand facing up. TE9 is on the back of the arm, never the palm side.
• Find the elbow tip. Bend your elbow and feel the hard point at the back — the olecranon. This is your top landmark.
• Find the wrist crease. Note the midpoint of the crease on the back of your wrist. TE9 lies on the imaginary line from the elbow tip down to that midpoint.
• Measure down from the elbow. Move about 5 of your own thumb-widths (roughly 10–12 cm in an average adult) down that line. On most people this lands a little above the halfway mark between elbow and wrist.
• Feel for the gap. Press gently across the area. You want the soft furrow between the radius and ulna, the two forearm bones, not the hard ridge of either bone.
• Check the feel. The spot often feels slightly tender or dense compared with the muscle either side of it, especially after heavy typing or gripping.

A note on measuring: traditional sources place TE9 five cun below the elbow tip. A cun is scaled to your own body, and the width of your own thumb at the knuckle is the usual stand-in. Use your thumb, not someone else's.

If you cannot feel a clear furrow, do not hunt for a magic millimetre. What is agreed across sources is the line, the side of the arm, and the rough distance below the elbow. Working a broad patch of that area with flat finger pressure is a reasonable and conservative approach for self-care.

How do you apply pressure to TE9?

1. Get settled. Sit down and rest the forearm on a table or your lap, palm facing down, muscles relaxed. Tense muscle makes the furrow between the bones hard to feel.
2. Use the pad of the thumb. Place the flat pad of the opposite thumb on the spot. Avoid fingernails and avoid the pointed tip of the thumb, which concentrates force on a small area.
3. Press slowly inwards. Build pressure over two or three seconds, aiming towards the gap between the bones. Stop at firm but comfortable — a dull ache is fine, a sharp or stinging feeling is not.
4. Hold or circle. Hold steady for 30 to 60 seconds, or make small slow circles without the skin sliding under your thumb.
5. Breathe out as you press. Slow breathing is doing some of the work in most self-acupressure routines, and it costs nothing to use it deliberately.
6. Release and repeat. Ease off over a couple of seconds, rest 10 seconds, and repeat two or three times. Then swap arms if you want to do both.
7. Keep sessions short. Two or three minutes per arm is plenty. Once or twice a day is a sensible ceiling for a self-care routine.

Stop straight away if you feel electric tingling, pins and needles, numbness in the hand or fingers, or pain that shoots towards the wrist. Nerves run through the deep forearm, and that feeling means you are pressing on one. Lighten up, shift a few millimetres, or stop for the day.

Also stop if the area stays sore the next day, if the skin bruises, or if the symptom you were working on is getting worse rather than better. Acupressure is self-applied finger pressure and nothing more; there is no skin-breaking technique on this page and none is needed.

What is TE9 traditionally used for?

• Ear problems and hearing. Classical sources link TE9 to deafness and ear complaints, because the Triple Energizer channel ends at the ear. No human trial has tested finger pressure at TE9 for hearing loss or tinnitus, so this is tradition only. Sudden hearing loss is a medical urgency and needs a doctor, not a point.
• Sore throat and lost voice. Old texts list Sidu for sudden hoarseness and throat pain. There is no controlled human evidence for this use. A sore throat that lasts more than a week, or comes with high fever or trouble swallowing, needs assessing.
• Toothache and jaw pain. TE9 appears in traditional lists for toothache. Nothing tested supports it, and a painful tooth is a dental problem with a dental cause. Pressure may distract you; it will not treat decay or infection.
• Forearm and elbow aching. This is the most plausible use, because the point sits directly in the forearm muscles that tire from gripping, typing and lifting. Gentle self-massage of tired muscle is reasonable self-care, though trials specifically on TE9 do not exist.
• One-sided headache and migraine. Some traditional and modern protocols include Triple Energizer points for head pain on the side of the skull. Evidence for acupressure in headache is small, short-term and mostly unblinded, and none of it isolates TE9.

Across the board the pattern is the same: a long traditional record, and almost nothing in the way of tested human results for this specific point. The broader acupressure literature is made up of small studies, often without a convincing dummy treatment, so placebo and attention effects are hard to separate out.

That does not make TE9 useless as a self-care habit. It does mean you should treat any confident claim about what it does — including claims made in videos — as unproven until someone tests it.

Are there tips for using TE9 effectively?

• Find the furrow, not the bone. Run a fingertip side to side across the back of the forearm first. The two bony ridges are obvious once you look for them, and TE9 lives in the soft gap between them.
• Measure with your own thumb. Cun are scaled to the person, so use the width of your own thumb at the knuckle to step the 5 thumb-widths down from the elbow tip. Borrowed measurements land in the wrong place.
• Relax the arm fully. Let the forearm rest dead weight on a surface. Holding the arm up tightens the muscles and buries the landmark you are trying to feel.
• Work both arms. Tradition treats the point on both sides, and for tired forearms it simply makes sense. Do one side, then the other, rather than overworking one spot.
• Pair it with the obvious fix. If your forearms ache from a keyboard or a tool, change the grip, raise the screen and take breaks. Pressure on TE9 will not out-argue eight hours of bad posture.
• Keep the pressure honest. Firm and dull is the target. Harder is not better, and bruising a forearm achieves nothing except a sore forearm.
• Track it for two weeks. Note the symptom score before and after each session. If nothing shifts in a fortnight, you have your answer and can stop spending time on it.
• Do it when you are warm. After a shower or a short walk, muscle is more pliable and the furrow is easier to feel.
• Keep nails short. Long nails push you onto the fingertip and risk marking the skin, especially on thinner older skin.

One broader tip: use TE9 as a prompt for two quiet minutes, not as a treatment you expect to replace anything. The breathing and the pause are the parts most likely to be doing real work.

What do people get wrong with TE9?

• Expecting a cure. The commonest error by far. TE9 has no tested power over hearing loss, toothache or migraine, and treating it as a fix delays care that might actually help.
• Pressing the wrong side of the arm. TE9 is on the back of the forearm, palm facing down. Points on the palm side belong to different channels entirely, so working the inner forearm is not TE9 at all.
• Confusing it with the wrist points. TE5 and TE6 sit low on the forearm, close to the wrist crease, and they are far better known. TE9 is much higher up, about 5 thumb-widths below the elbow tip. Videos often muddle them.
• Landing on bone. Pressing the hard ridge of the radius or ulna instead of the soft furrow between them. It hurts, achieves nothing, and can leave the bone surface tender.
• Pushing through nerve pain. Treating electric tingling or numbness in the fingers as a sign the point is "working". It is a sign you are compressing a nerve. Ease off immediately.
• Grinding away for twenty minutes. Long, hard sessions bruise the forearm and sensitise the area. A couple of minutes of firm, comfortable pressure is the whole technique.
• Using it on an injured arm. Pressing near a recent forearm fracture, a fresh wound, a burn or a surgical site because the point "is on that side". Skip the arm, not the caution.
• Ignoring the pattern of symptoms. One-sided hearing loss, a tooth abscess or a headache unlike any you have had before are all signals to get examined, not to press harder.

A final one worth naming: believing that because a point is old, it must be safe. Age tells you people used it, not that it suits your arm, your medication or your medical history.

What does the research on TE9 actually say?

No useful human research on TE9 (Sidu) specifically was found. There are no controlled trials testing finger pressure at this point for hearing problems, hoarseness, toothache, headache or forearm pain.

That absence matters more than it might look. It does not mean TE9 has been tested and failed; it means nobody has run the study. So any claim you read about what Sidu does for the ears or the voice is tradition being repeated, not a result being reported.

Where TE9 does occasionally appear is inside multi-point acupuncture protocols, alongside several other points, in trials that needled rather than pressed. Those studies describe what the researchers did. Even when such a trial reports a benefit, the design cannot tell you which point contributed, or whether finger pressure would do anything comparable. Reporting that a trial needled a point is not the same as evidence for that point.

The wider acupressure literature gives useful context. Most trials are small, run for a short time, and cannot blind participants — people know whether a thumb is pressing on them. Attention, expectation and the simple act of resting all push results in a positive direction. A handful of uses have better support than that, with PC6 for nausea and vomiting being the clearest example in the whole field, backed by repeated controlled trials. TE9 is nowhere near that standard, and it would be dishonest to imply otherwise.

What you can reasonably take from this: TE9 is a recognised classical point with a respectable traditional pedigree and an empty evidence file. Using it as a short, gentle self-massage habit for a tired forearm is low-risk. Using it in place of assessment for hearing loss, dental pain, a new headache pattern or persistent arm pain is not.

If better research appears, this page will say so. Until then, the honest grade is insufficient.