ST38 a Magical Acupoint for Frozen Shoulder

 Tiejun Tang

Frozen shoulder (adhesive capsulitis) is a common shoulder disorder characterised by shoulder pain, capsular fibrosis, and restricted active and passive ranges of movement. Its estimated prevalence in the general population worldwide is approximately 2–5%. A UK primary care study cited in the British literature reported a prevalence of 8.2% in men and 10.1% in women of working age ^[1].

Conventional Western medical treatment generally involves oral non-steroidal anti-inflammatory drugs (NSAIDs) to relieve pain and suppress inflammation. Oral or intra-articular corticosteroids may also be prescribed in some cases. Clinical evidence suggests that intra-articular corticosteroid injections offer certain advantages in terms of short-term pain relief and functional improvement in early-stage frozen shoulder. However, they cannot guarantee reversal of established capsular fibrosis. In patients with diabetes, corticosteroid injections may also cause a temporary rise in blood glucose levels ^[2].

According to Traditional Chinese Medicine (TCM), the underlying pathogenesis of frozen shoulder can be summarised as a combination of deficiency at the root and excess at the manifestation (ben xu biao shi). The internal causes primarily involve deficiencies of Qi and Blood, together with Liver and Kidney insufficiency. External pathogenic factors and manifestations include invasion by Wind, Cold and Dampness, trauma, overuse injuries, and stagnation of Qi and Blood.

Acupuncture is one of the principal TCM approaches to treating this condition. In addition to selecting local points around the shoulder, there is a remarkable distal acupuncture point that can produce striking therapeutic effects. I have frequently used this technique in my clinical practice. In many cases, a single needle insertion can provide immediate pain relief and improve the range of shoulder movement.

This point is known as Tiaokou (ST38). I would like to share this clinical technique and explore its possible mechanisms.

1. Location of the Acupuncture Points

• Tiaokou (ST38): Located on the anterolateral aspect of the lower leg, 8 cun below Dubi (ST35), approximately one finger-width lateral to the anterior border of the tibia. It belongs to the Stomach Meridian of Foot-Yangming.
• Chengshan (BL57): Located on the posterior aspect of the lower leg, in the depression below the junction of the two heads of the gastrocnemius muscle. It belongs to the Bladder Meridian of Foot-Taiyang.

2. Needling Technique

• Patient positioning: The patient sits or lies supine, with the knee sufficiently flexed to expose the lower leg.
• Needle insertion: A long acupuncture needle, usually approximately 3-4 cun in length, is inserted at Tiaokou (ST38). The needle is directed obliquely or transversely towards Chengshan (BL57), with an insertion depth generally of 3–3.5 cun.
• Needle manipulation and movement: Once Deqi (the characteristic needling sensation, often described as soreness, numbness, distension or heaviness) has been achieved, a reducing needling technique involving rotation is applied. While the needle is being manipulated, the patient is instructed to move the affected shoulder slowly, gradually increasing the range of movement.
• Needle retention: The needle is generally retained for 15–30 minutes. Treatment is usually given twice weekly.

3. Clinical Research Evidence

A published systematic review and meta-analysis included 19 randomised controlled trials involving 1,944 participants. The findings suggested that acupuncture at Tiaokou (ST38), whether used alone or in combination with local shoulder acupuncture points, may have beneficial therapeutic effects. These included improvements in overall clinical response rates and Constant–Murley scores, as well as reductions in visual analogue scale (VAS) pain scores in patients with shoulder adhesive capsulitis ^[3].

4. Exploring the Possible Mechanisms

4.1 Myofascial Chains and the TCM Meridian-Muscle Theory

Needling between Tiaokou (ST38) and Chengshan (BL57) may influence tissue tension in the shoulder through mechanical force transmission within the myofascial system. This could provide a possible explanation for the TCM therapeutic principle of treating an upper-body disorder through stimulation of a distal point in the lower limb.

Furthermore, myofascial trigger points (MTrPs) may generate both local pain and referred pain at distant sites. This provides another possible explanation for the use of distal acupuncture in the management of shoulder pain ^[4].

4.2 Nervous System Regulation and Central Pain Modulation

Tiaokou (ST38) is located in the tibialis anterior region on the anterolateral aspect of the lower leg, whereas Chengshan (BL57) lies in the posterior compartment, in the region of the gastrocnemius and soleus muscles.

Transverse needling between these two points may stimulate multiple layers of tissue, including the skin, subcutaneous fascia, muscles, interosseous membrane and deeper connective tissues, thereby activating different types of somatic sensory afferent fibres.

Deep mechanical stimulation may deform and stretch fascial connective tissue, activating fibroblasts, mast cells and mechanosensitive ion channels. This may promote the release of ATP, adenosine, histamine and other signalling molecules, initiating local neuroimmune responses ^[5–6].

These local responses may contribute to peripheral pain modulation and interact with the nervous system's central pain-regulatory pathways.

5. Clinical Experience and Conclusion

Throughout my decades of clinical practice, I have found that penetrating needling from Tiaokou (ST38) towards Chengshan (BL57) can produce rapid and often remarkable improvements in patients with frozen shoulder.

It is a non-pharmacological treatment that, when performed appropriately, can provide considerable pain relief and improve shoulder mobility. Its simplicity and potential for rapid clinical effects make it a particularly interesting acupuncture technique.

The clinical results I have observed suggest that this approach deserves further scientific investigation, particularly regarding its neurophysiological and myofascial mechanisms.

Reference

1. Linsell L, et al. Prevalence and incidence of adults consulting for shoulder conditions in UK primary care; patterns of diagnosis and referral. Rheumatology (Oxford). 2006 Feb;45(2):215–221.
2. Rupani N, et al. British Elbow and Shoulder Society patient care pathway: Frozen shoulder. Shoulder Elbow. 2025 Apr 23;17(4):351–363.
3. Yang C, et al. Acupuncture at Tiaokou (ST38) for shoulder adhesive capsulitis: What strengths does it have? A systematic review and meta-analysis of randomised controlled trials. Evid Based Complement Alternat Med. 2018 Apr 22;2018:4197659.
4. Liu J, et al. Theoretical connotation of penetrating acupuncture of Tiaokou point through Chengshan point for scapulohumeral periarthritis based on fascia theory. New Chinese Medicine. 2025;57(18):131–135.
5. Langevin HM, Churchill DL, Cipolla MJ. Mechanical signalling through connective tissue: a mechanism for the therapeutic effect of acupuncture. FASEB J. 2001;15(12):2275–2282.
6. Goldman N, Chen M, Fujita T, et al. Adenosine A1 receptors mediate local anti-nociceptive effects of acupuncture. Nat Neurosci. 2010;13(7):883–888.