Wei Zhong – Bl-40

English translation: Supporting Middle or Middle of the Crook

International identity number: Bl-40, UB-40, Urinary Bladder 40

Point Associations:

  • He Sea Point
  • Earth Point
  • Lower He Sea Point of the Urinary Bladder
  • Lumbar Command Point


In the middle of the popliteal fossa. Midpoint of the transverse crease of the popliteal fossa, between the tendons of biceps femoris and semitendinosis.

Needle insertion:

Perpendicular insertion 1.0 – 1.5 cun, or prick the popliteal vein with the three-edged needle to cause bleeding.


  • Clears Heat
  • Resolves Dampness
  • Relaxes the sinews
  • Removes obstructions from the channel
  • Benefits the lumbar region and knees
  • Cools Blood
  • Eliminates stasis of Blood
  • Clears Summer Heat
  • Activates the channel and alleviates pain
  • Benefits the Bladder

Wei zhong (Bl-40) is one of Ma Dan Yang’s ‘Twelve Heavenly Star Points’, long considered the pre-eminent list of the most important acupuncture points.

Wei Zhong (Bl 40) as the Lumbar Command point, is an excellent point for any low back condition, acute or chronic, muscle spasm. It is one of the main points for heat conditions such as summer heat, heatstroke and heat exhaustion. He-Sea points are where the Qi of the meridian collects and goes deep into the body. He-sea points are known to indicated treat rebellious Qi and diarrhoea. It is also known to help skin conditions, itching, oozing, inflammation, etc.. Good local point for leg a/or knee pain.

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Disclaimer: This article is not intended to diagnose or assess. The information provided is not to be considered a substitute for consultation with a qualified health care practitioner.