Small Intestine MeridianSI9

Jianzhen 肩貞

For reference only · not a substitute for diagnosis or treatment

Short answer

Back of the shoulder, below and behind the joint, 1 cun above the top of the rear armpit fold.

See it in 3DRotate the body and peel back the skin to see the bones and muscles beneath.
Open the 3D Acupoint Map →

🖼See it in pictures

Jianzhen — ① Where on the body? — **① Where on the body?**

Jianzhen — Textbook view — skin on the left, muscle and bone underneath on the right — **Textbook view — skin on the left, muscle and bone underneath on the right**
Location and structures come from our 3D model; only the drawing style was refined with AI. Labels are added by us.

Jianzhen — ③ Under the skin — **③ Under the skin**
Scapula · Teres major muscle · Long head of triceps brachii · Deltoid

Rendered straight from the 3D model at the computed location. The glowing ring marks Jianzhen.

On this page

Where is Jianzhen?
How do I find it on my body?
Before you press
How has it been used traditionally?
FAQ

1Where is Jianzhen?

Back of the shoulder, below and behind the joint, 1 cun above the top of the rear armpit fold.

With the arm against the body, it lies behind the deltoid.

Beneath the point

Scapula · Teres major muscle · Long head of triceps brachii · Deltoid

Our 3D measurement · In our 3D model: on the back skin 1 cun (21.8 mm) above where the skin gap between arm and trunk ends at the back (end of the rear armpit fold).

2How do I find it on my body?

Let the arm rest against the body.
Find the upper end of the rear armpit fold (posterior axillary fold).
Press 1 cun straight above it.

What is a “cun”?

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.

📖 Words explained

long head of triceps brachii: The head of triceps that starts on the shoulder blade, below the shoulder socket. It runs down behind the armpit.
posterior axillary fold: The fold at the back of the armpit when the arm is at the side, made by latissimus dorsi and teres major.
teres major: A round, column-shaped muscle running from near the lower corner of the shoulder blade to the front of the humerus. It helps form the back fold of the armpit and pulls and turns the arm inward.

3Before you press

⚠ Do not press when

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?

A point of the Small Intestine meridian behind the shoulder joint. Not to be confused with GB21, whose Korean name is spelled the same.

From traditional texts — not a claim of effect.

?FAQ

Where exactly is Jianzhen?

Back of the shoulder, below and behind the joint, 1 cun above the top of the rear armpit fold. With the arm against the body, it lies behind the deltoid.

How do I find Jianzhen?

Let the arm rest against the body. Find the upper end of the rear armpit fold (posterior axillary fold). Press 1 cun straight above it.

What should I watch out for?

Avoid broken or swollen skin and press only to a comfortable level. Acupressure is not a substitute for medical care.

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Sources

Location: WHO Standard Acupuncture Point Locations in the Western Pacific Region (2008), p. 92
Standard comparison: Chinese national standard GB/T 12346-2021 (Nomenclature and location of meridian points), p. 15
Korean anatomical terms: KMLE medical dictionary (Korean Medical Association terms)
Classical source: Zhenjiu Jiayi Jing vol. 3 (Wikisource edition)
Classification and traditional-use cross-check: AcuAtlas dataset (CC BY 4.0)

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.