How come when nail grow, the flesh under them doesn’t come forward along with the nail as it grows?

Question

Nails have a fleshy bottom layer attached to them that somehow doesn’t come forward with the nail as it grows, why is that?

In: Biology

Answer 1

The flesh of the nail bed is actually a very thin epidermis. It’s one of the reasons your nails appear red because the the dermis underneath is full of blood vessels. Your nail grows over this epidermis starting from the nail fold, an area under the cuticle. The nail grows towards the tips of your fingers over the nail bed, while the cells of the nail bed contribute to the thickness of your nail. Just like the cells of the epidermis on the rest of your skin, the cells of the nail bed that contribute to your nail fill will keratin, flatten, and die, causing them to detach from their neighbors. This is why the flesh isn’t pushed forward as the nail grows.