Acupuncture: Measuring the body

A proportional measure

寸 cùn

The cun does not measure centimetres: it measures proportions of the body being treated. That is why the same point falls in different places on a tall adult and on a child, and why measuring with your own fingers is the most repeated mistake of the early years.

1 cun

the width of the patient's thumb

1.5 cun

index and middle finger together

3 cun

the four fingers together

Golden rule

always the patient's hand

Common mistake: Using your own fingers on a patient of very different build. The point shifts by several centimetres.

Bone first, count second

Points are not found by eye: you find a bone landmark that does not move and count from there. Reversing the order — counting first and confirming later — is what produces locations that shift from session to session.

The wrist crease

origin for most of the forearm

Lower border of the kneecap

reference for the leg

Navel and pubis

divide the abdomen into 5 cun

Spinous processes

number the back

Common mistake: Locating with the patient in one posture and needling in another. The landmark has moved with them.

To locate the point 3 cun below the kneecap and one finger-breadth lateral to the tibial crest, what do you do first?

1. Palpate until you find a tender dip
2. Find the lower border of the kneecap and measure from there with the patient's hand
3. Measure three breadths of your own fingers

Which segment does each proportional measure belong to?

• Elbow crease to wrist crease: 12 cunArmTorsoLeg
• Navel to the upper border of the pubis: 5 cunArmTorsoLeg
• Knee crease to the outer ankle: 16 cunArmTorsoLeg
• Armpit to elbow crease: 9 cunArmTorsoLeg
• Lower border of the kneecap to the inner ankle: 15 cunArmTorsoLeg
• Between the two nipples: 8 cunArmTorsoLeg

Order the steps for locating a point.

1. Put the patient in the posture you will needle in↑↓
2. Identify the bone landmark↑↓
3. Measure the proportion with the patient's hand↑↓
4. Palpate for the dip or the change in texture↑↓
5. Confirm with the patient's reaction to pressure↑↓

Why is the proportional system especially useful in children?

1. Because in children the points are in different places
2. Because in children precision does not matter
3. Because proportions hold even when size changes, so one rule works for any build