ST-38 (Tiao Kou) Ribbon Opening

What does ST-38 Tiao Kou do?

Tiao Kou ST-38 is the Stomach channel's point on the middle of the lower leg, and its recorded work is unusual: it expels wind-damp and relieves pain in the leg locally, and it benefits the shoulder — a region at the opposite end of the body. Sacred Lotus sources & references record both actions directly. The second is what the point is famous for. ST-38 is the classical distal point for the frozen shoulder, and it is one of the clearest examples in the whole repertoire of a point used for a region it is nowhere near.

• Benefits the shoulder — the recorded action that defines this point in modern practice. It is used for pain, stiffness and restricted movement of the shoulder, and it is characteristically needled while the patient moves the affected shoulder. This is a distal action in the strict sense: the point is treated at the leg and the intended effect is at the arm.
• Expels wind-damp and alleviates pain — the local action, and the one the classical indication list is built on: aching, heavy, cold or painful legs and knees, the presentation the tradition reads as wind-damp obstruction of the channel.
• Activates the channel and benefits the leg and foot — for weakness, numbness and impaired movement of the lower leg and foot, and for pain along the front of the shin where the Stomach channel runs.
• Relieves abdominal pain — the recorded action that follows from the channel rather than from the location. The Stomach channel of Foot Yang Ming runs the length of the trunk, and its leg points carry abdominal indications for that reason.

A note on what this point is not. Queried directly against our own records, ST-38 carries no special-point classification at all — it is not a five-shu point, not a Source, Connecting or Cleft point, not a Back-Shu or Front-Mu point, and not a Confluent point. Its immediate neighbours do: ST-36 Zu San Li is the He-Sea and Earth point and ST-40 Feng Long is the Connecting point, both held here. ST-38's standing rests entirely on documented clinical use, and that is worth saying because it makes the point unusual in a different way: it is one of the very few unclassified points with a body of clinical trial evidence behind it.

Source: Sacred Lotus sources & references (existing action record; Stomach channel confirmed and the absence of any special-point classification queried directly, alongside the ST-36 and ST-40 classifications); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 163); Chinese Acupuncture & Moxibustion (p. 155); cross-referenced against multiple online sources.

What is ST-38 Tiao Kou used for?

Tiao Kou ST-38 is used above all for the frozen shoulder — pain and restricted movement of the shoulder joint — and, locally, for numbness, soreness and pain of the knee and lower leg and for weakness of the foot. The indications below are those carried in Sacred Lotus sources & references together with those set out in the standard reference literature. They describe traditional use, not proven treatment. This is a low-hazard point; the reference facts are set out under needling.

• Pain and restricted movement of the shoulder — the point's principal modern indication
• Frozen shoulder (adhesive capsulitis) and shoulder periarthritis
• Inability to raise the arm
• Numbness, soreness and pain of the knee and leg
• Weakness and impaired movement of the foot
• Coldness and aching of the lower leg
• Pain along the front of the shin
• Atrophy and weakness of the leg muscles
• Abdominal pain
• Cramp and spasm of the calf
• Heaviness of the legs

Source: Sacred Lotus sources & references (existing indication record); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 163); Chinese Acupuncture & Moxibustion (p. 155).

Where is ST-38 Tiao Kou, and how is it used in practice?

Tiao Kou lies on the front of the lower leg, about a finger's breadth to the outer side of the sharp front edge of the shin bone, at roughly the midpoint of the lower leg. Sacred Lotus sources & references give it two ways that come to the same place: eight cun below Du Bi ST-35 at the knee, and midway between the knee joint line and the bony bump on the outer ankle. It sits in the run of Stomach-channel points that descends the shin — ST-36, ST-37, ST-38, ST-39, ST-40 — all of them the same distance out from the shin's front edge except ST-40, which our own records place one finger-breadth further lateral than ST-38.

In practice ST-38 has two quite separate lives, and they are worth separating. As a local point it is unremarkable: one of several on the shin used for aching, heavy, weak legs. As a distal point for the shoulder it is one of the best-known single points in acupuncture, and it is used in a distinctive way — needled on the leg while the patient actively moves the painful shoulder, so that the movement and the needling happen together. That combination of a distant point and active movement of the affected part is the technique the point is associated with, and it has been tested directly (see below).

Why is a point on the leg used for the shoulder?

This is the interesting question about ST-38, and it deserves a straight answer: the classical reasoning is offered in three forms, none of them decisive, and the point's real standing is empirical. Set out honestly, the arguments are these.

• The same-name channel pairing. The Stomach channel is Foot Yang Ming; the Large Intestine channel is Hand Yang Ming, and it passes directly over the shoulder — Jian Yu LI-15 sits in the hollow at the front of the shoulder, held in this library. Classical theory pairs the hand and foot channels of the same name and allows one to be treated through the other. On that reading, ST-38 reaches the shoulder because Foot Yang Ming and Hand Yang Ming are one channel system in two halves.
• The Stomach channel's own course. The Stomach channel does not run over the point of the shoulder, but it crosses the front of the shoulder girdle at Que Pen ST-12 in the hollow above the collarbone before descending the chest. That gives the channel a real, documented presence in the region, which is more than can be said for most distal-point claims.
• The mirror correspondence between the limbs. A long-standing principle in acupuncture treats the arm and the leg as images of one another — shoulder answering to hip, elbow to knee, wrist to ankle — and treats a painful joint through its counterpart on the opposite limb. On the mirror reading, the mid-shin answers to the mid-upper-arm and the treatment is a correspondence rather than a channel connection.
• What the reasoning does not settle. The three explanations are not the same explanation, and none of them predicts why this point rather than ST-37 or ST-39 should be the shoulder point. The honest position is that ST-38's shoulder use is an empirical finding recorded in the classical literature and carried forward because it appeared to work, with the theory supplied afterwards. That is worth stating plainly on a page about a point whose entire reputation rests on it.

One piece of modern evidence bears on the question directly. A pilot brain-imaging trial randomised 24 patients with one-sided chronic shoulder pain to needling ST-38 on the same side as the pain or on the opposite side. Both groups improved; shoulder function improved more in the opposite-side group; and the two produced measurably different patterns of brain activity, with the anterior cingulate cortex implicated in the opposite-side response (Zhang S et al., J Pain Res 2018;11:505–514, PMID 29563830, PMC5846304). A companion analysis of the same 24 patients, using a different network measure, reached the same conclusion that the two sides act by different routes (Neural Plast 2020;2020:5701042, PMID 32377180, PMC7197008). These are 24-patient pilot studies of brain activity, not efficacy trials, and nothing about clinical superiority should be read into them. What they do establish is that needling ST-38 for a shoulder complaint is followed by measurable, side-dependent changes in the brain — which is a real finding about the mechanism of a distal point.

Which points is ST-38 combined with?

• With Cheng Shan BL-57 — the classical through-needling. The technique most associated with this point is a long insertion from Tiaokou on the front of the leg directed back toward Chengshan BL-57 in the calf behind it, used not for the leg but for the shoulder. Our own BL-57 record carries the same combination from its side. It has been tested: 60 patients with shoulder periarthritis were randomised to the Tiaokou-to-Chengshan needling alone or the same needling with active shoulder movement during treatment; both groups improved on pain, movement and daily-activity scores, and the movement group improved more (Zhongguo Zhen Jiu 2018;38(8):815–818, PMID 30141290). It is a small, single-centre, unblinded trial, but it is a direct test of the technique this point is known for.
• With the local shoulder points — Jian Yu LI-15 at the front of the shoulder, Jian Liao SJ-14 behind it, Jian Zhen SI-09 and Nao Shu SI-10 at the back, all held here. The standard structure is distal point plus local points, and most of the trial literature uses ST-38 alongside shoulder points rather than instead of them.
• With Tiao Kou alone. Unusually, this point is also used entirely by itself. It is one of the small number of points with a published record of single-point treatment, and the systematic review below assessed both single-point and combined use.
• With Zu San Li ST-36 — the He-Sea and Earth point three levels above on the same channel, added where the leg itself is weak or where the treatment is aimed at building qi rather than at the shoulder.
• With Yang Ling Quan GB-34 — the Hui-Meeting point of the sinews at the outer knee, held here, added wherever tendons and ligaments are the target.
• With Tiao Kou needled during movement — not a point pairing but the technique the trial evidence supports most directly: the shoulder is actively moved while the leg point is retained (PMID 30141290).

Source: Sacred Lotus sources & references (both location records, channel, and the ST-35, ST-36, ST-37, ST-39, ST-40, BL-57, LI-15, SJ-14, SI-09, SI-10 and GB-34 records queried directly); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 163); Chinese Acupuncture & Moxibustion (p. 155); PMID 29563830 (PMC5846304); PMID 32377180 (PMC7197008); PMID 30141290; cross-referenced against multiple online sources.

Where is ST-38 located?

• A Manual of Acupuncture (p. 163): On the lower leg, midway between the tibiofemoral joint line (level with the popliteal crease) and the prominence of the lateral malleolus, one finger-breadth lateral to the anterior crest of the tibia.
• Chinese Acupuncture and Moxibustion (p. 155): 8 cun below Dubi (ST-35), and one finger breadth (middle finger) from the anterior border of the tibia.

How is ST-38 Tiao Kou needled?

Stated plainly: ST-38 is a low-hazard point. It lies on the front of the lower leg beside the shin bone, there is no body cavity, no organ and no great vessel in the needle path, and the depth our records carry — perpendicular 0.5 to 1.0 inch — is an ordinary limb depth rather than a bounded safety figure. The one thing worth understanding precisely is the classical through-needling toward Cheng Shan BL-57, which is a much longer insertion and crosses more structures than the ordinary one. Everything below is recorded as neutral reference data describing what the textbooks and the published literature state. It is not instruction, this page does not teach technique, and 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 0.5 to 1.0 inch, with moxibustion applicable — the same range our records carry at Xia Ju Xu ST-39 immediately below, and comparable to the figures at the other shin points. No caution is attached to it in our record, which is itself informative given how many points in this library carry one.
• Deadman & Al-Khafaji (p. 163) and Chinese Acupuncture & Moxibustion (p. 155) record a comparable perpendicular range, and additionally record the through-needling toward Cheng Shan BL-57 as a documented alternative — a long insertion directed from the front of the leg toward the calf behind. Neither attaches a hazard caution of the kind both attach to the thoracic, abdominal, orbital and occipital points.
• Depth has actually been compared in a trial at this point, which is rare. Eighty patients with shoulder periarthritis were randomised to four ways of treating the same point: through-needling, insertion to 40 mm, insertion into the subcutaneous tissue only, and sham needling. The reported effective rates were 100 per cent, 68.4 per cent, 52.6 per cent and 38.0 per cent respectively, with the through-needling group significantly better than the other three, and the authors' conclusion was that different needling depths at Tiaokou produce different results (Zhongguo Zhen Jiu 2006;26(10):729–731, PMID 17117574). Read this carefully: it is a small, single-centre, unblinded study reporting an implausibly perfect 100 per cent effective rate in its treatment arm, and effective-rate outcomes of this kind are a weak measure. It is recorded because it is the only published comparison of needling depth at this point, not because it settles anything.
• Moxibustion is recorded as applicable and is commonly used, particularly where the leg is cold and aching.

What actually lies beneath

• The ordinary insertion. The needle passes through skin and thin subcutaneous tissue into tibialis anterior, the muscle that runs down the outer side of the shin bone. Deep within the anterior compartment, against the interosseous membrane, lie the deep peroneal (deep fibular) nerve and the anterior tibial artery and vein. At the recorded depth of half an inch to an inch the needle is within the muscle belly, and contact with a nerve produces a sharp or electric sensation rather than injury. This is an ordinary limb point.
• The through-needling is a different proposition, and should be understood as one. An insertion carried from ST-38 toward BL-57 travels from the anterior compartment of the leg, through or past the interosseous membrane that separates the shin bone from the outer leg bone, and into the deep posterior compartment behind it — where the tibial nerve and the posterior tibial vessels run — before reaching the calf muscles. That is a long insertion through several fascial compartments rather than a deep one within a single muscle. The reference texts record it as a documented classical technique; it is recorded here as a fact about what the technique crosses, not as a caution about what it causes.
• Honest limit. We could not source any published case report of injury at ST-38, and no imaging study measuring a safe depth at it. None is needed in the way it is at the thoracic, abdominal and cranial points: there is no cavity to enter. Where a point is low-hazard, the useful thing is to say so plainly rather than to import a warning from elsewhere.

Risk in proportion

A meta-analysis of prospective clinical studies estimated serious adverse events in acupuncture at approximately 1 per 10,000 patients and around 8 per million treatments, with about half of all recorded events being bleeding, pain or flare at the needle site, placing acupuncture among the safer treatments in medicine (Bäumler P et al., BMJ Open 2021;11:e045961, PMID 34489268). Systematic reviews of the Chinese case literature reach the same conclusion about where the events cluster: at points over the chest, the abdomen, the neck and the orbit, attributed chiefly to improper technique (He W et al., PMID 22967282; Zhang J et al., Bull World Health Organ 2010;88(12):915–921C, PMID 21124716, PMC2995190). ST-38 is not in that group. The systematic review of trials at this point specifically set out to assess safety as well as effectiveness and did not identify a safety signal (PMID 29849707).

Source: Sacred Lotus sources & references (existing needling record; the ST-36, ST-37, ST-39 and BL-57 needling records queried directly for comparison); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 163); Chinese Acupuncture & Moxibustion (p. 155); PMID 17117574; PMID 29849707 (PMC5937513); PMID 34489268; PMID 22967282; PMID 21124716 (PMC2995190) — each verified resolvable and checked for retraction status before citation.

What does the name Tiao Kou mean?

Tiao Kou means "Ribbon Opening" — tiao, a strip, band, ribbon or long narrow thing, and kou, an opening or mouth. Sacred Lotus sources & references translate it exactly that way; "Line Opening", "Stripe Mouth" and "Narrow Opening" are the other renderings in circulation, and they are all reaching for the same image. The name is descriptive of the ground: at this level of the lower leg the muscle bellies either side of the shin bone leave a long, narrow slot along the bone's outer edge, and the point sits in that slot. Straighten and flex the ankle and the strip opens and closes.

There is a second reading worth knowing, though it is a modern gloss rather than a classical one: that the "opening" is the passage through which the point reaches the shoulder — the narrow channel by which a point on the leg gets somewhere else. It is a pleasing idea and it is not what the name says. The classical sense is topographical.

Why does ST-38 have no special-point classification?

Because it simply does not have one, and that is worth knowing rather than glossing over. Queried directly, our own records show ST-38 with no five-shu, Yuan-Source, Luo-Connecting, Xi-Cleft, Back-Shu, Front-Mu or Confluent classification. It sits in the middle of a stretch of shin where its neighbours are heavily classified: ST-36 Zu San Li is the He-Sea and Earth point of the Stomach channel and one of the most-used points in the medicine; ST-40 Feng Long is the Connecting point and the tradition's principal point for phlegm. The reference literature additionally records ST-37 Shang Ju Xu and ST-39 Xia Ju Xu as the Lower He-Sea points of the Large Intestine and Small Intestine respectively — a classification our own category records leave blank for those two points, so it is attributed here to the reference texts rather than to our own holdings.

That leaves ST-38 as the unclassified point in a classified neighbourhood, and it makes its reputation the more striking. Almost every famous point in acupuncture is famous partly because of a classification. This one is famous only because of what it is used for.

Is there research on ST-38 Tiao Kou for frozen shoulder?

Yes — and ST-38 is one of the few points in the entire repertoire with a systematic review devoted to it by name. The review's verdict is encouraging and, in its own words, weak: nineteen trials, nearly two thousand patients, and "the majority of the trials were determined to be of low quality". Both halves of that sentence belong on this page.

• The systematic review and meta-analysis. Researchers at Beijing University of Chinese Medicine searched eight databases without language restriction for randomised trials comparing acupuncture at Tiaokou with other treatments — local shoulder points, non-steroidal anti-inflammatory drugs and others — for shoulder adhesive capsulitis. Nineteen randomised controlled trials involving 1,944 participants met the criteria. Pooled results favoured acupuncture at Tiaokou, used alone or combined with shoulder points, on effective rate, on the Constant-Murley shoulder score and on the visual analogue pain scale. The authors' own conclusions are the important part and are reproduced faithfully: the evidence is "encouraging", the majority of the included trials were of low quality, and the results "need to be strengthened by additional RCTs of higher quality" (Yang C et al., Evid Based Complement Alternat Med 2018;2018:4197659, PMID 29849707, PMC5937513).
• Why "low quality" matters here specifically. The trials in this literature are overwhelmingly single-centre, unblinded, and reported as "total effective rates" — a composite outcome graded by the treating clinician, which is among the weakest measures in clinical research and is prone to inflation. Several report effective rates of 96 to 100 per cent. Those numbers should be read as what they are: a house style of reporting, not a measurement of effect size. The two outcomes in the review that do mean something specific are the Constant-Murley score and the visual analogue scale, both of which are validated instruments, and both of which favoured the treatment.
• The largest individual trial. A multi-centre randomised single-blind trial allocated 257 patients with shoulder periarthritis to oral anti-inflammatory medication alone or the same medication combined with acupuncture at Tiaokou. The combined group did better on both pain relief (96.0 per cent against 91.7 per cent) and improvement in shoulder movement (86.3 per cent against 59.4 per cent), the second difference being the substantial one (Guo CQ et al., Zhongguo Zhen Jiu 2006;26(8):544–546, PMID 16941969). Note what the design shows and does not: it shows acupuncture added to medication beating medication alone, which cannot distinguish a specific effect of the point from the effect of receiving an additional treatment.
• The needling-technique trial. Eighty patients, four arms, comparing through-needling, 40 mm insertion, subcutaneous insertion and sham at the same point, with through-needling best (PMID 17117574). Discussed under needling above; small and unblinded, and its perfect 100 per cent effective rate in the treatment arm should be treated with caution.
• The needling-with-movement trial. Sixty patients randomised to Tiaokou-to-Chengshan through-needling with or without active shoulder movement during the treatment; both improved, the movement group more (PMID 30141290). This is the most useful of the small trials, because it isolates one variable — the movement — rather than comparing acupuncture against nothing.
• The brain-imaging pilots. Twenty-four patients with one-sided chronic shoulder pain, randomised to same-side or opposite-side needling at ST-38, showed different patterns of brain activity by side, with opposite-side needling producing greater functional improvement (PMID 29563830, PMC5846304; companion analysis PMID 32377180, PMC7197008). Pilot mechanistic studies in a small sample; they do not establish clinical superiority of either side.
• The fair summary. ST-38 has more point-specific clinical evidence than almost any other single acupuncture point, and that evidence is consistently positive and consistently of low methodological quality. A reader should take from it that the traditional use is real, well-documented and widely practised, and that it has not yet been tested to a standard that would settle the question.

How does ST-38 compare with the points around it?

Zu San Li ST-36, three cun below the knee, is the He-Sea and Earth point of the Stomach channel and one of the most-used points in acupuncture; where the intention is to build qi rather than to reach the shoulder, ST-36 is the point. Shang Ju Xu ST-37 lies between them, and Xia Ju Xu ST-39 just below ST-38; the reference literature records both as Lower He-Sea points, of the Large Intestine and Small Intestine respectively. Feng Long ST-40 lies at the same height as ST-38 but one finger-breadth further out — our own ST-40 location record defines it in exactly that relation to Tiaokou — and it is the Stomach's Connecting point and the tradition's principal point for phlegm. The two are easy to confuse for that reason and the distinction is purely lateral: nearer the shin bone is ST-38, further out is ST-40. Cheng Shan BL-57 lies in the calf directly behind and is the target of the classical through-needling. Du Bi ST-35 at the knee is the landmark from which our own record measures this point's height. And for the shoulder itself, Jian Yu LI-15, Jian Liao SJ-14, Jian Zhen SI-09 and Nao Shu SI-10 are the local points ST-38 is normally used alongside. All are held in Sacred Lotus sources & references.

Source: Sacred Lotus sources & references (name, translation, channel, the absence of any special-point classification, and the ST-35, ST-36, ST-37, ST-39, ST-40, BL-57, LI-15, SJ-14, SI-09, SI-10 and GB-34 records queried directly); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 163); Chinese Acupuncture & Moxibustion (p. 155); PMID 29849707 (PMC5937513); PMID 16941969; PMID 17117574; PMID 30141290; PMID 29563830 (PMC5846304); PMID 32377180 (PMC7197008) — each verified resolvable and checked for retraction status before citation; cross-referenced against multiple online sources.