Which of the following lists the main components of the nail unit?

• A. Nail plate and nail bed
• B. Nail plate, nail bed, matrix
• C. Nail plate, nail bed, nail folds, hyponychium, eponychium (cuticle), matrix, and surrounding skin
• D. Nail plate, matrix

Answer: (C)

The main idea is that a nail unit is a collaboration of several structures that work together to form and protect the nail. The most complete list includes the nail plate (the hard, visible part), the nail bed (the skin underneath that supports the plate), the matrix (the tissue that actually creates the nail plate), the nail folds (the side skin that frame the nail), the hyponychium (the skin under the free edge at the tip), the eponychium or cuticle (the seal at the base that protects the matrix), and the surrounding skin around the nail. Each part has its role: the matrix drives growth, the nail plate sits on the nail bed, the folds and surrounding skin keep the nail anchored and protected, and the cuticle and hyponychium help guard against infection at the proximal and distal ends. This combination is why the full set is the best choice.