Cun Measurement
The cun is used for acupuncture to measure and locate acu-points on anyone's body.
Since everyone's body is of a different size and shape, using a person's inborn measurement system makes finding the points easy.
The process starts with the measurement of one cun.
This is done two ways:
(a) using the width of the distal inter-phalangeal joint of the thumb (first finger) or
(b) using the distance between the distal and proximal inter-phalangeal joints of the 3rd (middle) finger.
All other specific measurements are outlined in the diagrams below.
When in doubt in measuring, the thumb (1 cun) or the four-finger method (3 cun) can always be used in a pinch.
