BL38 Superficial Cleft

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

BL38 (Fuxi, “Superficial Cleft”) is an acupuncture point on the Bladder Meridian. It is located on the posterior thigh, 1 cun superior to BL39 (Weiyang), medial to the biceps femoris tendon. It relaxes sinews, invigorates channels, alleviates pain.

Location

On the posterior thigh, 1 cun superior to BL39 (Weiyang), medial to the biceps femoris tendon.

Needling

Perpendicular insertion 1.0-2.0 cun.

TCM functions

Relaxes sinews, invigorates channels, alleviates pain.

Indications

Contraction of the elbow and arm, numbness and pain in the popliteal fossa.

Clinical notes

Fuxi is primarily utilized for local pain and stiffness in the popliteal fossa and posterior thigh, often associated with hamstring issues or knee pain. While less commonly used than its neighbors BL37 and BL40, it serves as a valuable adjunctive point for relaxing sinews and invigorating the Bladder channel in this region. It can be effective for acute muscle spasms or localized discomfort.

On the Bladder channel

BL38 is one of 67 points on the Bladder Meridian. Nearby points:

Frequently asked questions

Where is BL38 located?

BL38 (Fuxi) is located on the posterior thigh, 1 cun superior to BL39 (Weiyang), medial to the biceps femoris tendon.

What is BL38 used for?

BL38 relaxes sinews, invigorates channels, alleviates pain. Common clinical indications include contraction of the elbow and arm, numbness and pain in the popliteal fossa.

How is BL38 needled?

Perpendicular insertion 1.0-2.0 cun.

Which meridian is BL38 on?

BL38 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.