Bladder 33 (BL 33) Zhong Liao — Central Bone-Hole

This point, one of the eight liao points, benefits the lower burner and relieves lumbosacral pain.

Bladder 33 (BL 33) Zhong Liao 中髎 — Central Bone-Hole

Location

On the sacrum, in the third posterior sacral foramen (S3).

Anatomy

Over the third posterior sacral foramen; the lateral sacral artery; the dorsal ramus of the third sacral nerve.

Actions & Functions

  • Benefits the lower burner and the genitals
  • Regulates menstruation and urination
  • Relieves lumbosacral pain

Indications

Irregular menstruation, abnormal vaginal discharge, difficult urination, constipation, and lumbosacral pain.

Needling

1.0-1.5 cun, perpendicular insertion into the foramen.

Moxibustion Suitability

Suitable for moxibustion.

Point Combinations

With BL-31, BL-32 and BL-34 for lower-burner disorders.

Classical Text References

One of the eight liao points of the sacrum.

Cautions & Contraindications

Caution in pregnancy.

Latest Research

Latest peer-reviewed research on this point will be summarised here, with citations linked to PubMed, via our research integration.

About Attilio

Doctor of Chinese medicine, acupuncture expert and author of My Fertility Guide and My Pregnancy Guide.

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PubMed research

Acupuncture Identified as a Key Neuromuscular Intervention for Post-Stroke Swallowing Difficulties

Research summary (Acupuncture): Neuromuscular-related interventions for post-stroke dysphagia: a comprehensive narrative review. - Frontiers in neuroscience, 2026.