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.
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