Cracks in nails
For as long as I can remember, I have had lines in my toe nails. These lines, or cracks run from the front edge of the nail back to the base of the nail. It seems that the nail is laminated and these lines or cracks are mostly in the top layer or lamination.
Recently I have had one of these cracks appear in one of my finger nails. The crack is in the top layer, but by the outer end of the nail it goes all the way through the nail.
In doing day to day work, this crack is continually snagging on things and eventually I have to cut the nail back to the "quick" to get it to stop snagging.