Which part of the nail is primarily responsible for nail growth?

• A. Nail bed
• B. Nail plate
• C. Lunula
• D. Nail matrix

Answer: (D)

Nail growth comes from the nail matrix, the tissue under the proximal nail fold that actively divides to form new cells. As these cells keratinize, they harden and are pushed outward, creating the nail plate that we see as the visible nail. The lunula is simply the visible portion of the matrix, often lighter in color, signaling the matrix beneath, but the matrix itself is the source of new nail cells. The nail bed provides nourishment and support to the nail but does not generate new nail cells, and the nail plate is the hard keratinized structure that results from matrix activity. If the matrix is damaged, growth or the shape of the nail can be affected, underscoring why the nail matrix is the primary driver of nail growth.