Bladder

BL40

委中 · Weizhong

Middle of the Crook

Middle of the back-knee crease. Command point for the back.

He-sea · Earth point of the Bladder · Command point for the back

Use caution

System

Channel: Bladder (BL)
Element: Water
Yin or yang: yang
Organ system: Bladder
Region: Hip and leg
Limb rule: Foot Taiyang

Open the Bladder page

Where it is

Exact middle of the crease behind the knee, between the two tendons, when the knee is slightly bent.

Nearby: The popliteal artery and tibial nerve run through this crease. You can feel a pulse. Do not press the pulse.

Traditionally said to

He-sea and earth point of the Bladder, and the command point for the back. A famous point for low-back pain in channel teaching. Also historically bled for summer-heat. Do not bleed it.

What people look up

Pain relief Local muscle tension Low back

Acupressure

Knee soft, press just beside the midline of the crease, off the pulse, 20–40 seconds. If you feel a beat, move off it.

When not to press: Do not press a pulse, a swollen knee, or a calf that is hot and tender (possible clot — urgent care).

About 30–90 seconds is the usual window, unless the step above is shorter. Stop if pain, dizziness, or anything unusual shows up.

Licensed practice only

Needle depth, angle, electroacupuncture

Textbook language for students. Not instructions. A cun is a body-inch on that person, not a ruler inch. Do not needle yourself.

Depth

Common textbook range: about 1–1.5 cun perpendicular, or a prick to bleed in classical practice. The artery is why this is a clinic point.

Angle

Perpendicular, in the midpoint, avoiding the artery. Bleeding is not a home method.

Electroacupuncture

Introductory charts rarely assign a standard electroacupuncture setting here. Clinics that use current choose frequency and intensity for that person. No milliamp figure is given, because copying one would be misleading.