BL39 Weiyang

Reviewed by · Licensed Acupuncturist & TCM Physician · Last reviewed June 2026

BL39 (Weiyang, “Weiyang”) is the Lower He-Sea of the Sanjiao point of the Bladder Meridian. It is located on the lateral aspect of the popliteal fossa, medial to the tendon of the biceps femoris muscle. The point is found with the knee flexed, in the depression at the lateral end of the transverse popliteal crease. It regulates the Sanjiao, opens the water passages, resolves dampness, and strengthens the lumbar region and legs.

Location

On the lateral aspect of the popliteal fossa, medial to the tendon of the biceps femoris muscle. The point is found with the knee flexed, in the depression at the lateral end of the transverse popliteal crease.

Needling

Perpendicular insertion 0.5 to 1.0 cun. Caution should be exercised to avoid the common peroneal nerve, which is located medially to the biceps femoris tendon in this area.

TCM functions

Regulates the Sanjiao, opens the water passages, resolves dampness, and strengthens the lumbar region and legs..

Indications

Axillary swelling, emotional instability , body heat, sudden fainting with corpse-like rigidity (, ), flaccidity and numbness , urinary dripping, difficult urination, lower abdominal hardness and pain radiating to the genitals, involuntary urination, leg cramping and pain, inability to bend or extend the leg, stiffness and pain in the lumbar region preventing flexion and extension, chest fullness, epilepsy, shivering with white urine, urinary retention , genital twitching ..

Lower He-Sea of the Sanjiao

Clinical notes

As the Lower He-Sea point of the Sanjiao, Weiyang is a primary point for regulating the water passages, particularly in the lower jiao. It is classically indicated for urinary disorders such as retention, difficulty, and incontinence, especially when accompanied by lower abdominal tension. Its location also makes it effective for stiffness and pain in the lumbar spine and popliteal fossa, particularly conditions involving leg cramping or difficulty with flexion and extension of the knee.

On the Bladder channel

BL39 is one of 67 points on the Bladder Meridian. Nearby points:

Frequently asked questions

Where is BL39 located?

BL39 (Weiyang) is located on the lateral aspect of the popliteal fossa, medial to the tendon of the biceps femoris muscle. The point is found with the knee flexed, in the depression at the lateral end of the transverse popliteal crease.

What is BL39 used for?

BL39 regulates the Sanjiao, opens the water passages, resolves dampness, and strengthens the lumbar region and legs. Common clinical indications include axillary swelling, emotional instability , body heat, sudden fainting with corpse-like rigidity (, ), flaccidity and numbness , urinary dripping, difficult urination, lower abdominal hardness and pain radiating to the genitals, involuntary urination, leg cramping and pain, inability to bend or extend the leg, stiffness and pain in the lumbar region preventing flexion and extension, chest fullness, epilepsy, shivering with white urine, urinary retention , genital twitching.

How is BL39 needled?

Perpendicular insertion 0.5 to 1.0 cun. Caution should be exercised to avoid the common peroneal nerve, which is located medially to the biceps femoris tendon in this area.

Which meridian is BL39 on?

BL39 is a point on the Bladder Meridian (Zú Tài Yáng Páng Guāng Jīng).

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⚠️ This page is for general education and is not medical advice. Acupuncture is a traditional practice; evidence varies by condition and study quality, and individual results differ. It does not replace diagnosis or treatment by a licensed professional. Always consult a qualified acupuncturist or physician.