What is the structure of nails?

Nail development structure: nails come from the skin. Like skin, it is formed by the gradual differentiation of ectoderm, lateral layer and mesothelium after 9 weeks of embryo. Fingernails are divided into deck, nail bed, nail fold, nail groove, nail root, nail epithelium, nail hypodermis and so on. Deck is equivalent to skin layer, and nail fold is the part where skin bends into nail groove. The nail bed consists of auxiliary layer, basal layer and dermal reticular layer, which is equivalent to epidermis. Its lower part is directly fused with phalangeal periosteum.

The posterior nailfold covers the nail root and migrates to the nail epithelium. Before the nail bed, there is nail skin. The nailfold of nail bed does not participate in the growth of deck, and the growth of nail is formed by the proliferation, keratinization and forward penetration of nail matrix cells at the root of nail. But the nail bed controls the growth of nails of a certain shape. If the nail bed is damaged, the nails will grow abnormally. Nail beds and nail roots have rich vascular uses. These provide rich nutrition for nail regeneration.

Extended data:

Characteristics of healthy nails

1, uniform color, light pink.

2, toughness, moderate thickness, moderate hardness, not easy to break.

3, the surface is smooth, shiny, no layering, lines, etc.

4, nail edge neat, no defect (except for external reasons).

5. The half-moon shape (commonly known as crescent moon) at the root of nails accounts for one-fifth of the ascending order of nails, and milky white is appropriate (some people are born without it).

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