BL 40 — Wěi Zhōng (委中) — Middle of the Crook
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1. Overview
BL 40 — Wěi Zhōng (委中) — is an acupuncture point on the Bladder meridian. Its English name, Middle of the Crook, reflects the point’s classical character and location. It is one of the most clinically important points in acupuncture practice and is used regularly in the treatment of a range of conditions.
I am Dr (TCM) Attilio D’Alberto, a member of the British Acupuncture Council with over 25 years of clinical experience. I use BL 40 as part of individually tailored acupuncture prescriptions at my clinic in Wokingham, Berkshire.
2. Location
At the midpoint of the transverse crease of the popliteal fossa, between the tendons of biceps femoris and semitendinosus.
3. Actions
- Relaxes the sinews and activates the meridian
- Clears Heat and cools Blood
- Resolves Dampness
- The command point for the back
4. Indications
- Acute and chronic low back pain — the single most important distal point for back pain
- Hip pain and sciatica via the Bladder meridian
- Knee pain and popliteal tightness
- Heatstroke and febrile disease
- Skin conditions — urticaria and eczema from Heat in the Blood
- Vomiting and diarrhoea from acute summer-Heat
5. Needling
Perpendicular insertion 0.5–1.0 cun, or prick to bleed with a three-edged needle for acute back pain. Avoid deep insertion to avoid the popliteal artery.
Important: Acupuncture should only be performed by a fully qualified practitioner. Never attempt self-needling. All needles I use are sterile, single-use and disposed of immediately after treatment in a clinical sharps container.
6. Clinical notes
BL 40 is the He-Sea and Earth point of the Bladder meridian and is designated as the command point for the back. The classical saying — 'For disorders of the back, seek Weizhong' — reflects its central importance in all back conditions. Bloodletting at BL 40 (pricking to cause a few drops of blood to flow) is one of the most powerful TCM techniques for acute severe low back pain and is dramatically effective in many cases. In modern practice, cupping is frequently applied at BL 40 alongside needling for musculoskeletal back conditions.
7. Treatment at my clinic
I use BL 40 as part of tailored acupuncture prescriptions for conditions including Back pain, Sciatica, Hip pain, Knee pain. Each treatment is individually designed following a full TCM assessment.
I see patients in person at my clinic in Wokingham, Berkshire. Visit the prices page for consultation fees. Return to the acupuncture points directory or the acupuncture main page.
