Secret hand gestures in paintings (www.ncbi.nlm.nih.gov)

During the Renaissance period, hands were as important a focus of attention as the face was, because they were the only other visible area of the body. Hence, representation of the position of the hands became a decorative element that was almost as important …

It’s a lot of text with some illustrative images, but if you can get through it all, it’s very interesting. This stuff has been going on for centuries.