What does it mean to pinch people's fingers in fortune telling?

Do you need to look at the body parts to calculate divination?

In the fortune-telling of mountain doctors, there are external and internal phases, that is, the so-called internal and external phases that dominate life. If the eight characters are incomplete or unknown, fortune-telling has individual phases, generally speaking, it is to look at the five senses, hands and feet, and other parts of the body. But now most of them are mixed up, most of them are liars. Divination doesn't need these things. I hope they can help 1 1.