What are the white semi-circles at the bottom of our finger and thumb nails?

Asked by: Calum Ball, Worthing

Your fingernails and toenails are made from keratin protein that is secreted by a layer of living tissue at the base of the fingernail called the nail matrix. The crescent moon shape, or lunula, is the part of the matrix that pokes out from under the flesh of your finger.

In some people it barely protrudes and is only really visible on the thumb and big toe. The lunula looks white because the epidermis is thicker beneath the matrix and it blocks the pink colour from the blood vessels below.

Read more:

• Why do my fingernails grow faster in a hot country?
• Do fingernails and hair really keep growing after death?

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