Which are the main parts of the nail unit?

• A. Nail plate, nail bed, nail matrix, cuticle, and surrounding skin (perionychium)
• B. Nail plate only
• C. Hair shaft
• D. Epidermis and dermis

Answer: (A)

The nail unit is built from several parts that work together to grow and protect the nail. The visible hard portion is the nail plate, which sits on the nail bed—the living tissue just beneath it. Growth happens at the nail matrix, a region tucked under the base of the nail where new cells are produced. The cuticle, or eponychium, helps seal the area to protect the new nail from infection as it forms. Surrounding skin, known as the perionychium, includes the proximal and lateral nail folds and the skin around the nail.

So, the main parts are the nail plate, nail bed, nail matrix, cuticle, and the surrounding skin. Choosing only the nail plate misses the tissues essential for growth and protection, while other options either refer to unrelated structures like the hair shaft or to general skin layers (epidermis and dermis) that aren’t specific to the nail unit.