What is the name of the living skin at the base of the nail plate covering the matrix?

The living skin at the base of the nail plate that covers the matrix is known as the eponychium. This structure serves as a protective barrier for the newly growing nail and the underlying matrix, which is crucial for nail formation. The eponychium helps prevent pathogens from entering and provides essential hydration to the matrix, ensuring healthy nail growth. Its role is significant in maintaining the overall health and integrity of the nail unit.

In contrast, the hyponychium is found under the free edge of the nail and provides a protective seal between the nail and the skin underneath. The bed epithelium refers to the skin beneath the nail plate, and the free edge is the part of the nail that extends beyond the fingertip. Each of these structures has its own function in nail anatomy, but the eponychium specifically pertains to the living skin at the nail’s base, making it the correct answer.