What are the half moons on your finger nails?

Lunula, also called the lunule, is the whitish, half-moon-shaped area at the base of your fingernails. It is part of the nail matrix, the area of the nail bed from which the nail grows.

- Lunula (pl. lunulae) derives from the Latin word for “small crescent moon.”

- The lunula is not only found in humans but is present on primates and some carnivores as well. While many primates have lunulae on all their digits, not all do. Likewise, some carnivores have lunulae and others do not.

- The lunula often appears pinkish in darker-skinned individuals.

- The lunula is the point at which your fingernail begins growing (the nail bed).

- Fingernails grow slower in the winter and faster in the summer, just as hair growth on the head is faster in the summer and slower in the winter.

- Fingernails are made of keratin, the same material that makes up hair.

- Fingernails grow at a rate of approximately one millimeter per week, but this growth can vary depending on a person’s age, overall health, gender, and environmental factors such as weather.

- Your nails grow twice as fast as your toenails.

- The lunula may disappear after a nail has been injured, but it will usually return after the nail has been repaired.

There is no scientific evidence that the lunula is a way to diagnose a person's health.