Nails are hard protective keratinous plates that form the dorsal surface of the terminal phalanx of the digits. The visible nail plate is composed of keratinized protein, which is continually produced by the nail matrix, located beneath the proximal nail fold. This matrix is the primary source of nail growth, pushing the plate forward over time. Underlying structures include the nail bed, which provides vascularization and nutrients to the nail plate, and the cuticle, which seals the area where the plate meets the skin. Proper function of the nail involves mechanical support for the digits and protection of the underlying tissue from minor trauma.