Xiaochangshu 小腸兪
Sacrum, 1.5 cun out from the median sacral crest, level with the first posterior sacral foramen.
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Sacrum · Posterior layer of thoracolumbar fascia
Rendered straight from the 3D model at the computed location. The glowing ring marks Xiaochangshu.
On this page
1Where is Xiaochangshu?
Sacrum, 1.5 cun out from the median sacral crest, level with the first posterior sacral foramen.
It is also level with Shangliao (BL31).
Sacrum · Posterior layer of thoracolumbar fascia
2How do I find it on my body?
- Find the bony point under the dimple above each buttock: the posterior superior iliac spine.
- A line joining the lower edges of the two spines crosses the midline at the S2 spinous process.
- Midway from the posterior superior iliac spine to the S2 spinous process, feel for a dip: the second posterior sacral foramen (Ciliao, BL32).
- Move up from the second foramen: the next dip is the first posterior sacral foramen.
- At that height, press 1.5 cun out from the bony ridge down the middle of the sacrum (median sacral crest). This is half the 3-cun midline-to-shoulder-blade width.
A cun is a body-scaled unit of length. The precise way is to divide a bone length into equal parts (proportional bone cun); finger widths are a quick estimate.
- posterior layer of thoracolumbar fascia
- The outermost layer of the tough sheet that wraps the muscles of the lower back. Latissimus dorsi starts from it, and it covers erector spinae from behind.
- median sacral crest
- The bumpy vertical ridge down the middle of the back of the sacrum. It is made from the spinous processes of the sacral bones that fused together.
- spinous process
- The bony spike sticking backward from the middle of each spine bone. The row of bumps you feel down the middle of the back is these, and they serve as the counting marks for back points.
3Before you press
- Do not press this point during pregnancy.
- Points over the low back and sacrum are traditionally avoided in pregnancy (WHO acupuncture safety guidelines, 1999).
- Avoid broken or swollen skin and press only to a comfortable level.
- Acupressure is not a substitute for medical care.
4How has it been used traditionally?
- Classified as the back-shu point of the Small Intestine (Zhenjiu Jiayi Jing) — a historical classification, not a claim of effect.
From traditional texts — not a claim of effect.
?FAQ
Where exactly is Xiaochangshu?
Sacrum, 1.5 cun out from the median sacral crest, level with the first posterior sacral foramen. It is also level with Shangliao (BL31).
How do I find Xiaochangshu?
Find the bony point under the dimple above each buttock: the posterior superior iliac spine. A line joining the lower edges of the two spines crosses the midline at the S2 spinous process. Midway from the posterior superior iliac spine to the S2 spinous process, feel for a dip: the second posterior sacral foramen (Ciliao, BL32). Move up from the second foramen: the next dip is the first posterior sacral foramen. At that height, press 1.5 cun out from the bony ridge down the middle of the sacrum (median sacral crest). This is half the 3-cun midline-to-shoulder-blade width.
Can I press it during pregnancy?
Do not press this point during pregnancy.
What should I watch out for?
Do not press this point during pregnancy. Points over the low back and sacrum are traditionally avoided in pregnancy (WHO acupuncture safety guidelines, 1999). Avoid broken or swollen skin and press only to a comfortable level. Acupressure is not a substitute for medical care.
Sources
- Location: WHO Standard Acupuncture Point Locations in the Western Pacific Region (2008), p. 113
- Standard comparison: Chinese national standard GB/T 12346-2021 (Nomenclature and location of meridian points), p. 17 — same location
- Korean anatomical terms: KMLE medical dictionary
- Traditional-use cross-check: AcuAtlas dataset (CC BY 4.0)
- Classification source: Zhenjiu Jiayi Jing vol. 3, sec. 8 (back-shu line, 1.5 cun)
- Safety: WHO Guidelines on Basic Training and Safety in Acupuncture (1999), p. 20 — lumbosacral points in pregnancy
- 3D: computed on Z-Anatomy (CC BY-SA 4.0) · BodyParts3D © DBCLS
Positions computed from the WHO standard locations (2008) on Z-Anatomy (CC BY-SA 4.0) · BodyParts3D © DBCLS. For reference only — not a substitute for diagnosis or treatment. See a clinician if you are unwell.