The growth of the nail is longitudinal, that means that the cells grow from the root and they disappear when we cut our nails.
The fingernails of the hand, for an adult’s average, grow approximately 0.1mm up-to-date.
The growth in children is higher and in old people is lower.
The toenails  grow between a third and a fourth more slowly. So, in order to regain one fingernail delays between five or six months and one of the toenails between 15 and 18 months.
 
The fingernails are flexible in the children, transparent, of flat and convex surface.
In adults, the fingernail is harder and  resistant appraising always the presence of the half-moon at the cuticle’s zone.
In older people, the fingernail lose brilliance, it becomes opaque, grayish, fragile, and the half-moon tends to disappear.
A healthy fingernail has an oval shape, is flat and with a partially pink color. This pink color is due to the existing a blood flow in the bed of skin and to the transparent characteristics of the nail.
The fingernail then, as well as for its color like for its distinct forms, constitutes a mirror of our healthy status.

The structure of the fingernail is similar to the structure of the bones, 3 coats fix it:

 

The superficial coat is formed by cells that have lost its vitality and they accumulate fibrous material like keratins.

 

The intermediate coat is thicker, and it has the same origin than the superficial one but with alive close-knit cells among them and a less density of fibers  of keratin.

 

The deep coat, finally, are only two coats of cells that come from the bed of the skin.

The fingernail, is a flat and convex plate that covers and protects the fingertips.
This plate is formed by coats of keratin, repose on the bed of skin and has two well defined borders, one stuck directly to the skin zone and the other border free, curiously, in the zone of the free border we can observe a line that marks the beginning of the free area. s
In the border that is below the cuticle we find the root of the fingernail, its birth, this zone comes from a more whitish color than the rest of the nail and we observed a zone of half moon.

At this zone the skin that coats the fingernail has two faces and is called cuticle, it has an inner face  and the other one is external and its function is to protect the root of the nail.
The fingernails are formed in the same way of the skin, his principal component is the keratin, the principal difference between the skin and the fingernail is the percentage of water, the first one contains a 85 % and the fingernail only a 12%.
 

A. Proliferating matrix
B   Ungueal  furrow
C. Dorsal face
D. Ventral face
E  Eponiquio
F. Cuticle
G. Ungueal plate
H. Plantar corneous substance
I. Ungueal bed

1.Border of the nail
2. Yellow line
3.Lateral border
4.Ungueal plate
5.Lúnula
6.Cutícula
7.Eponiquio
8.Ungueal back fold

As we all know about in an ordinary form the fingernails are plates placed in the superior face of the extreme of the fingers of hands and feet. The surface of the skin covered by them is called the ungueal  bed.

The fingernail is surrounded by an area of skin “unguea lrodete”  and a zone of free growth.

The fissure that exists between the area of skin that surrounds the fingernail and the bed  is called “ungueal furrow.

The nearest edge to the cuticle zone is called the root of the nail. The visible part of the nail is called body of the nail and as we have previously stated it is surrounded by skin and it has a zone of free growth, this zone is called “distal portion” and it is extended forward, besides, it wears down in time or it is cut.

The aspect of the nail is semitransparent and permits that the color of the skin that lies under it shows up through it.

Stuck to the cuticle or the zone of the root, the fingernail has a whitish color and in the shape of a half moon, this half-moon normally is covered by the skin of the cuticle.

The plate of the nail is formed by dead remains of conical epithelial cells distributed in a  longitudinal form, that means lined in direction to the growth.

As the fingernail goes away forming itself in the matrix, it goes away moving forward the fingernail simply goes away sliding on the ungueal bed.

 Image anatom - a

A. Proximal fold

B. Cuticle

C. Lateral fold

D. Ungueal plate

E.Ungueal matrix

F. Lunule

G. Hiponiquio

 
 

 Image anatom - b

 A. Epidermis

B. Cuticle

C. Ungueal bed

D. Collagen fibers

E. Ungueal plate

F. Bone

G. Epidermis

H. Lateral border

I Hiponiquio