BL31 Upper Bone-Hole

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

BL31 (Shangliao, “Upper Bone-Hole”) is an acupuncture point on the Bladder Meridian. BL31 is in the 1st posterior sacral foramen, medial to the posterior superior iliac spine. It regulates menstruation, stops leucorrhea, benefits urination, strengthens the back and legs.

Location

BL31 is in the 1st posterior sacral foramen, medial to the posterior superior iliac spine.

Needling

Perpendicular insertion 0.8-1.2 cun.

⚠ Pregnancy: avoid — may stimulate uterine contraction (miscarriage / early-labour risk).
⚠ Reduce depth in thin patients — avoid deep perpendicular insertion.

TCM functions

Regulates menstruation, stops leucorrhea, benefits urination, strengthens the back and legs.

Indications

Irregular menstruation, leucorrhea, dysuria, enuresis, low back pain, muscular atrophy, pain, numbness and weakness of the lower extremities.

Clinical notes

Shangliao is one of the eight 'Bone-Hole' points (Ba Liao), which are highly effective for gynecological, urinary, and lower back issues due to their direct access to the sacral nerve plexus. It is particularly used for regulating menstruation, stopping leucorrhea, and benefiting urination, especially for conditions like dysmenorrhea, irregular menstruation, and difficult urination. It is often combined with other Ba Liao points for a stronger effect on the lower jiao.

On the Bladder channel

BL31 is one of 67 points on the Bladder Meridian. Nearby points:

Frequently asked questions

Where is BL31 located?

BL31 is in the 1st posterior sacral foramen, medial to the posterior superior iliac spine.

What is BL31 used for?

BL31 regulates menstruation, stops leucorrhea, benefits urination, strengthens the back and legs. Common clinical indications include irregular menstruation, leucorrhea, dysuria, enuresis, low back pain, muscular atrophy, pain, numbness and weakness of the lower extremities.

How is BL31 needled?

Perpendicular insertion 0.8-1.2 cun. Caution: ⚠ Pregnancy: avoid — may stimulate uterine contraction (miscarriage / early-labour risk). ⚠ Reduce depth in thin patients — avoid deep perpendicular insertion.

Which meridian is BL31 on?

BL31 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.