what is the skin that grows under the nail
Nail (anatomy) The nail bed is the skin beneath the nail plate.[8][unreliable source?] Like all skin, it is made of two types of tissues: the deeper dermis, the living tissue which includes capillaries and glands,[9][unreliable source?] and the epidermis, the layer just beneath the nail plate, which moves toward the finger tip with the plate. The epidermis is attached to the dermis by tiny longitudinal "grooves"[5] called matrix crests (cristae matricis unguis).[3][9] In old age, the nail plate becomes thinner, and these grooves become more visible.[5]
Vitamin D The skin consists of two primary layers: the inner layer called the dermis, composed largely of connective tissue, and the outer, thinner epidermis.[162] Thick epidermis in the soles and palms consists of five strata; from outer to inner, they are: the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. Vitamin D is produced in the keratinocytes[163] of two innermost strata, the stratum basale and stratum spinosum.[160]