Based on medical research fingerprints are fully formed somewhere between 16-20 weeks after conception, before some other organs in the body. And they never change, which we all know.
The volar pads that form the fingerprints are raised at different levels on the fingers, meaning that whorls are raised on the finger the highest amount where arches are flat and don't raise up on the volar pads. Peacocks and composites follow closely behind whorls, then loops, tented arches and arches. So the ranking system used to identify Life Purpose (highest ranked) and Life Lesson (lowest ranked) is based on the formation of the fingerprints on the volar pads.
But fingerprints are different from any other part of the hands because they don't change. So I understand fingerprints to be much more of an identification of a person's soul agreement. I don't lump them in with other hand markings because they stand on their own. That doesn't mean I don't include other hand markings in a session with clients. What it means is that from birth to death, regardless of any other hand markings, there is a reason for this person to be here and it's tangible.
There are other parts of the body that are just as significant for identification and don't change the same as fingerprints: voice, retina, walk, eye color, 8 basal cells at the base of the spine - just for what I arleady know about. And I'm sure there are other things I don't know.
All fingers matter because each of the 10 has a very specific purpose - including master and student path. And if a finger is the 'life lesson' finger, it creates valuable insights for a person to know obstacles that can be faced, understood, consciously chosen to make changes one step at a time. The combination of life purpose fingers and life lesson fingers creates an even more sophisticated understanding of what truly creates the highest possibility of satisfaction, joy and soul fulfillment. I'm grateful to Richard Unger for this addition to Hand Analysis in his way. It's helped me know myself more and many, many clients.