BL38 Floating Cleft

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

BL38 (Fuxi, “Floating Cleft”) is an acupuncture point on the Bladder Meridian. It is located on the posterior thigh, 1 cun superior to Weizhong (BL40), on the medial side of the biceps femoris tendon. It relaxes the sinews, alleviates pain, and benefits the lumbar region.

Location

On the posterior thigh, 1 cun superior to Weizhong (BL40), on the medial side of the biceps femoris tendon.

Needling

Perpendicular insertion 1.0 to 2.0 cun.

TCM functions

Relaxes the sinews, alleviates pain, and benefits the lumbar region..

Indications

Numbness of the leg, contraction of the sinews in the popliteal fossa, constipation, cystitis..

Clinical notes

Fuxi is a local point on the posterior thigh, primarily used for conditions affecting the leg and popliteal fossa, such as hamstring tightness, sciatica, and knee pain. Its classical indications also suggest a potential, though less common, use for urinary and bowel issues like cystitis and constipation, likely through its connection to the Bladder channel.

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 Weizhong (BL40), on the medial side of the biceps femoris tendon.

What is BL38 used for?

BL38 relaxes the sinews, alleviates pain, and benefits the lumbar region. Common clinical indications include numbness of the leg, contraction of the sinews in the popliteal fossa, constipation, cystitis.

How is BL38 needled?

Perpendicular insertion 1.0 to 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.