(1) Methyl (matrix): The methyl group is located at the root of the nail and its role is to produce the keratin cells that make up the nail. The nail contains capillaries, lymphatic vessels and nerves, and is therefore extremely sensitive. Damage to the nail means that the nail stops growing or grows abnormally (2) nail root: The nail root is located under the skin and is thin and soft. Its role is to promote the renewal of the nail by pushing the old cells to grow outward from the newly produced nail cells. (3) Cuticle and posterior nail edge (eponychium): The cuticle is a layer of skin that covers the nail root, which also covers the posterior nail edge. The posterior edge of the nail is the edge where the nail penetrates deep into the skin. (4) Nail arc (lunula): The nail arc is located at the connection between the nail root and the nail bed and is white and semilunar in shape. It is important to note that the nail cover is not firmly attached to the nail, but is only connected to it by the nail arc. (5) Nail plate: or nail plate. The nail plate is located between the finger skin and the front edge of the nail and is attached to the nail bed. The nail plate is made up of several layers of hard keratin cells and does not contain nerves or capillaries itself. When cleaning the dirt under the edge of the finger, do not go too deep to avoid hurting the nail bed or making the nail cover loose from the nail bed, or even fall off. (7) Nail bed: The nail bed is located underneath the nail and contains a large number of capillaries and nerves. Because of the capillaries, the nail bed is pink in color. (8) Free edge and hyponychium: The free edge of the nail is the part of the nail that extends from the top of the nail bed, and the thin layer of skin underneath the front edge of the nail is called the core. (9) Nail groove and nail wall: The nail groove is the depression of the skin along the perimeter of the nail, and the nail wall is the skin at the nail groove. The structure of the toenail is roughly the same as that of the fingernail. The growth and health of the nail depends on the health of the body, blood circulation and mineral content of the body.