The skin directly beneath the free edge of the nail is called the:

The hyponychium is the slightly thickened skin directly beneath the free edge of the natural nail, where the nail plate separates from the fingertip. It helps form a protective seal that guards against infection entering under the nail. (The matrix is the growth center, the lunula is the visible part of the matrix, and the nail bed lies under the attached nail plate.) Knowing the parts of the nail unit, including the hyponychium under the free edge, is part of the nail-science content on the exam.