Look at the base of your thumbnails. You probably have a crescent-shaped white marking at the end, scientifically known as the lunula. While most people possess this half-moon shape on their thumbs and big toenails, it's less common to have lunulas on your other fingers and toes.

The shape of the lunula varies by person and even by finger. In fact, the whitish color and formation is a result of the process of developing and maturing nail cells. Also, the shape of the lunula determines the eventual shape of the free edge, aka the part of the nail that grows past the finger.

Fun facts about lunulas:

  • The appearance of these crescent shapes often fades as we get older.
  • Lunulas start forming around the 14th week of gestation.
  • Lunulas can often be an indicator of health and well-being.