The nail plate is almost entirely comprised of a chemical called Keratin. This is the same substance that hair is made of. The Keratin is made of amino acids.

The nail plate is made from cells of Keratin, which are like eggs or seeds, and they incubate in the matrix until they are pushed out to form a nail plate. When they are being pushed out, the cells have not fully ruptured, and are white in color. This makes the area at the base of the nail, called the lunula, white in appearance.

Considering more about the matrix; It is located under the eponychium, a fairly safe place, though any damage to the matrix can cause permanent injury to future nail growth. The matrix is constantly producing more nail cells, and receives blood from local vessels to nourish the cells it is making.

Inside the cell is a "glue" like substance, this will come out when cells rupture then flatten. The nail plate is basically comprised of dead cells "cemented" together with this "glue". Nail plates and hair are both cross-linked with a special type of amino acid, called cystine. The nail cell contains much more cystine than the hair does, so nails are vastly stronger than hair.

The Proximal nail fold is the eponychium, commonly confused with the cuticle, which is on the underside of the eponychium. The laternal nail fold is commonly called the "walls". The distal nail fold is the hyponychium, the hyponychium is under the free edge, sealing the nail and the nail bed together.

The nail folds purpose is to seal out bacterium and pathogens, which can damage a nail growth and cause a fungus. The proximal nail fold prevents bacterium from damaging the matrix.

The true cuticle is on the underside of the eponychium, it sheds a non-living "skin" that adheres to the nail plate. The non-living skin that can be scraped off is commonly confused with peterygium.

True peterygium. is a scar like tissue which much be removed by a doctor.