Originally Posted by meliny
It is completely normal for people not to have nail half moons, or "lunule". However, if you once had prominent moons, and they have dissappeared in a relatively short period, COMBINED with nail darkening, then it could be a sign of a health condition. That being said, people's moons naturally dissappear as they get older. If it bothers you, ask your doctor. But I myself have never had moons (again, only tiny ones on my thumbs) and I'm in perfect health.
The 'moon' or 'lunula' you see is actually the leading edge of the matrix, which is where the nail plate cells are born. The moon is most prominent on the thumb nails and can be seen on the index fingers and the middle fingers, but is rarely seen on the ring fingers and (almost) never on the pinky fingers. This is natural!
If one has very thick natural nails, the moon will be more prominent as it developes more nail plate cells the longer it is and the more visible it is. If the nail plate is thin, one will rarely see the lunula (moon) on any of the nails.
If one sees a change in color of the lunula, it can signify an internal disorder that will require a physician to diagnose. Otherwise, not having a prominent lunula does not signify a 'health related' problem.