What is primarily responsible for the growth of a nail?

The germinal matrix is primarily responsible for the growth of a nail because it is the tissue located beneath the base of the nail, also known as the matrix. This area produces new cells that push older cells outward, leading to the growth of the nail plate. The matrix cells proliferate and keratinize to form the hard nail structure that we see.

When examining the other options: the eponychium, commonly referred to as the cuticle, protects the germinal matrix, and while it plays a role in nail health, it is not responsible for growth. The hyponychium is found beneath the nail's free edge and also serves a protective function but does not contribute to growth. Understanding the role of the germinal matrix is essential for recognizing how nail growth occurs and the importance of this structure in maintaining healthy nails.