The nail root of the fingernail is the base of the human nail. It’s also known as the germinal matrix. It is hidden beneath the skin within the nail sinus and attached to the growth matrix at the nail’s medial terminal end. Like the rest of the nail, it is made up of flattened keratin cells in a plate-like shape, lightly grooved on the surfaces above and below.
Within the nail root, the epithelial cells growing and dividing at the growth matrix become keratinized-mixed together and hardened with keratin, fibrous forms of amino acids containing sulfur compounds. This keratinization leads to the hardening of the nail bed and lends the nail its strength. Growth within the nail root adds about 3mm of nail bed each month, growing continuously and pushing the dead cells of the nail body (nail plate) forward along with the nail bed and into the free edge of the nail.