Nail Plate

The nail plate is mostly keratin, the same chemical substance that forms hair. Keratin is a protein made from amino acids. These special proteins form a strong, flexible material which we call the nail plate. The nail plate is made of many layers of dead, flattened cells. These plate-like cells are cemented to each other with a sticky substance. When many layers stick to each other they form a structure that resembles a mortar and brick wall. The nail plate is also called the natural nail.

After a keratin cells grows in the matrix it is pushed outward and slightly upward by newer cells. The new growth emerges from under the proximal nail fold at the eponychium (see Figure 1.2). As new cells leave the matrix, they push the older cells toward the fingertips. Eventually, each keratin cell will reach the end of the finger. The part of the nail plate that grows beyond the fingertip is called the free edge or the distal nail plate. Distal means “farthest from the attached end.” It is important to remember the difference between distal and proximal. Proximal means “nearest attached end”. Therefore, distal is the opposite of proximal. These words may seem strange at first, but they are important to understand.

The hard keratin plate protects the nail bed and fingertip. Thicker nail plates provide greater protection. Obviously, if the nail plate is thinned too much, it cannot properly protect the delicate tissue underneath. This is often seen in nails that are over manicured or filed. Over filing the natural nail is a leading cause of nail plate thinning and destruction.

When keratin cells leave the matrix they are plump and whitish in appearance. Before emerging from under the eponychium the cells flatten, become transparent, and lose their color. This explains why nail plates are normally colorless, except for the white half-moon at the cuticle.