Lunula is defined as which of the following?

• A. The edge that covers the bottom of the nail
• B. The white area of the nail, which is part of the matrix
• C. The fold of skin on the sides of the nail
• D. Prevents infection, moisture from getting under the skin

Answer: (B)

The main idea is the nail matrix—the tissue at the nail root that makes new nail cells. The lunula is the visible portion of that matrix, appearing as the white, crescent-shaped area at the base of the nail. Its whiteness comes from overlying thickened matrix tissue that is relatively avascular, so you see less color from underlying vessels. The other descriptions refer to different nail parts: the skin folds on the sides are the nail folds, and the protective role against infection and moisture involves the whole nail unit rather than this specific region.