Here's why and a more detailed explanation of nail growth:
* Nails grow from the nail matrix. The nail matrix is located beneath the proximal nail fold (the skin at the base of your nail) and is the actively growing part of the nail. Cells in the matrix divide and differentiate, producing the keratin that makes up the nail plate.
* The subdermis (hypodermis) is a deep layer. The subdermis is the deepest layer of the skin, composed primarily of fatty tissue and connective tissue. It's located beneath the dermis and is not directly involved in nail formation.
Layers Involved in Nail Growth:
* Nail Matrix: The germinative zone where nail cells are produced.
* Nail Bed: The skin beneath the nail plate that provides support and nourishment.
* Nail Plate: The hard, visible part of the nail, made of keratin.
* Dermis: The layer of skin beneath the epidermis (the outermost layer). The dermis contains blood vessels, nerves, and other structures that support the nail matrix and bed.
Therefore, the nails grow from the nail matrix, not from the subdermis. The subdermis is too deep and doesn't have the specialized cells needed for nail production.