BL-40 Weizhong
BL-40 Weizhong (委中) is a point on the Bladder meridian. In TCM theory it is described as influencing the channel's qi, and it is traditionally used in the context of the whole pattern rather than as a stand-alone remedy. This page explains how to locate it, what the tradition says about it, and how to press it safely.
Location
At the midpoint of the popliteal crease, behind the knee.
How to find it
Lie prone with the knee slightly bent. The point is in the center of the crease behind the knee.
Traditional functions
- He-sea point of the Bladder meridian
- Clears heat and benefits the low back
- Relaxes the sinews of the leg
Traditional uses
- Low-back pain in the classical description
- Knee stiffness
- Calf tension
- Skin irritation behind the knee
How to press it
Use very gentle pressure while lying down. Avoid pressing deeply into the crease.
Acupressure is generally a gentle practice. Use the pad of the thumb or finger, start with light pressure, and increase only to a comfortable level. A mild ache or warmth is common; sharp pain is a signal to ease off.
Safety
Important nerves and blood vessels run behind the knee. Do not press hard, and avoid this point with varicose veins or a history of clots.
How this is viewed today
BL-40 is common in acupuncture trials for low-back pain and knee osteoarthritis. Evidence is typically short-term and of low certainty.
Sources & further reading
- Huangdi Neijing (黃帝內經), c. 2nd century BCE.
- Nanjing (難經), c. 1st–2nd century CE.
- World Health Organization, Standard Acupuncture Nomenclature, 2nd ed., 1991.
- Deadman P, Al-Khafaji M, Baker K. A Manual of Acupuncture. Journal of Chinese Medicine Publications.
- National Center for Complementary and Integrative Health, Acupuncture: What You Need To Know.
Related: Bladder meridian · Acupoint library · BL-23 Shenshu · BL-57 Chengshan · GB-34 Yanglingquan · all twelve meridians