Proximal nail fold is best described as which structure?

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

Answer: (C)

The proximal nail fold is the skin fold at the base of the nail that overlaps the proximal nail plate, covering the nail matrix. This position lets it protect the growing nail and helps form a protective seal with the cuticle, reducing moisture and pathogen entry around the nail root. That protective role—preventing infection and moisture from getting under the skin—best matches the described structure. The other options point to different parts: the fold on the sides are the lateral nail folds, the edge that covers the bottom of the nail is the hyponychium at the distal end, and the white area is the lunula, part of the matrix.