What is the living skin at the base of the natural nail plate that covers the matrix area?

The living skin at the base of the natural nail plate that covers the matrix area is referred to as the eponychium. This structure is crucial as it serves as a protective barrier for the matrix, which is where new nail cells are generated. The eponychium is important for maintaining the health of both the nail and the surrounding skin by preventing bacteria and other pathogens from entering the area.

In contrast, the cuticle is the dead tissue that lies along the nail plate's edge, serving as a protective layer but does not cover the matrix itself. The perionychium refers to the skin that surrounds the entire nail unit, which includes the nail plate, eponychium, and surrounding skin. The nail bed is the skin beneath the nail plate that provides support but does not refer specifically to the area covering the matrix. Therefore, the specificity of the eponychium, as the living skin covering the matrix at the base of the nail plate, makes it the correct answer.