Nail Anatomy

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By peace | November 26, 2006

The nail plate is the actual nail, and it is composed of translucent keratin. Keratin is made up of compressed hard layers of a protein substance that is produced by the cells of the nail matrix. The pink appearance of the nail comes from the blood vessels located in the nail bed. The nail plate acts as a protective shield, shielding the delicate tissues of the underlying Nail Bed.

The nail matrix (nail root) is found beneath the skin under the proximal nail fold. The cells within the nail root produce the nail plate and most of the nail bed. The leading edge of the nail matrix is seen as a white, crescent shaped structure called the lunula.

The matrix is in fact the root of the nail. This area is not visible, it is hidden and protected by the Proximinal Nail Fold. The matrix produces keratin cells that make up the nail plate. As more and more cells are produced the older ones are pushed outwards and flattened, all this pushing and flattening results in the cells loosing their original white plumpish appearance. They eventually become transparent and become part of the nail plate.

Apart from producing the keratin cells that make up the nail plate, the matrix also determines the shape and thickness of the nail. The overall length of the matrix will determine the thickness of the nail; so the longer the matrix the thicker the nail. A short matrix produces fewer cells, as a result a thinner nail. Matrix shapes and sizes vary per person, a flat matrix will produce a flat nail and a curved matrix will produce of course a curved nail.

The matrix is the most important feature of the nail unit. Damage to the matrix can cause permanent damage to the appearance of the nail.

The nail folds protect the matrix. The Proximinal Nail Fold and the Lateral Nail Folds are part of our skin. The skin does not just end there, it in fact folds at the edges and continues beneath. This continuing skin acts as a protective barrier, it in fact protects and seals the matrix against bacteria and dirt that is common within our environment.

The cuticle (eponychium) is situated between the skin of the toe and the nail plate, fusing these structures together and providing a waterproof barrier. The cuticle helps to prevent micro-organisms and moisture from harming the nail matrix. The Eponychium is in fact not the true cuticle. The eponychium attaches closely to the nail plate and moves with it as the nail plate grows. This extra growth of eponychium is generally freed and pushed back during a manicure. The eponychium’s function is to act as a barrier seal to stop bacteria, infection from getting to the matrix.

We are constantly shedding dead skin cells throughout our daily life, the nail folds are no exception. The skin on the underside of the nail folds sheds constantly as the nail plate grows and rubs (sloughs) against it. These dead skin cells attach to the nail plate and become visible as the nail grows. This attached skin is referred to as the Ptygerium, dead skin cell or the true cuticle. This needs to be removed regularly in order to prevent a build up.

The Lunula is often referred to as “moons”. The lunula is in fact the front end of the matrix. The whitish half moons are keratin cells that have not yet been completely flattened and still have some of their content. Not everyone has visible lunula’s The lunula is normally more prominent on the thumbs. The shape of the lunula determines the shape of the free edge/distal edge.

The hyponychium is the area between the nail plate and the tip of the toe. It is the junction between the free edge of the nail and the skin at the tip of the toe. The hyponychium is a waterproof barrier at the end of the nail plate, which protects the nail bed from germs and moisture.

How fast does the nail grow?
The overall growth of the nail within one month is approximately 3mm. However this does vary from person to person. To completely out grow a nail can take up to 6 months. As mentioned, growth rate does vary from person to person, there are many contributing factors such as; weather, health, age and a well balanced diet. The nail tends to grow faster in our early years, reaching its peak around the age of 10-14 and then the nail growth gradually slows down, as we get older. Growth is accelerated in the summer, during pregnancy and during sleep. Poor blood circulation, malnutrition, certain illnesses and some medications can slow down the growth rate. Each nail grows at a different rate. The smallest nail that we often refer to as our “pinkie” is the in fact the slowest, then the thumbs. The index finger generally grows at an accelerated rate in comparison to the others.

Brittle nails tend to have a low water content. The water content will effect the flexibility of the nails. Water content can vary from 10% to 30%. Nail varnishes and oils will prevent loss of water and encourage flexibility.