There is no single unit of measurement for location of relief points as the size and shape vary from person to person. To counteract this problem a new unit of measurement came into existence called Acupressure-inch (Ai). It is based on an individual person depending upon the ratio-proportion of his/her body parts.

For e.g.

• The distance from mid-point of eyebrows to the highest point of the natural hairline at the forehead is equal to three Ai.
   

• The distance from the farthest wrist fold to the outer corner point of the bent elbow is equal to twelve Ai.
   

• The distance from the highest point on the ankle bone on the outer side of feet to the bottom of the heel is three Ai.
   

• The width of four fingers measured across the knuckles is three Ai.
  

By understanding these measurements one can judge the actual length of the Acupressure-inch (Ai) on the body.