Parts of Nails
The parts of the nail are the nail matrix, cuticle, lunula, nail bed, natural nail plate, free edge, the posterior, lateral and anterior nail fold.
1. Nail matrix
The hidden part of the nail covered by the posterior nail fold. It contains the matrix (nail root), a mass of germ-cells that produces the nail. A part of it extends from beneath the posterior nail fold under the lunula. (It is exactly separated from the nail bed where a definite curve is formed at the edge of the lunula). The size and form of the matrix (lunula- curve) determines the size, form and thickness of the nail plate. If the matrix gets hurt it can result in a long- lasting injury! The new keratin cells produced in the matrix push older cells forward. (This is called the keratinization process which moves forward).
During the keratinization process the fat, full, living cells gradually lose their internal material and nucleus, they become flattened (and translucent) then they waste away. At the end of the process they become dead, flat, translucent keratinous plates and are organized into fibres in a longitudinal direction.
A band of skin attached closely to the nail plate providing protection to the nail matrix. It is made up of soft keratin which fills up the layer between the nail root and epithelium. The epidermis protects the newly grown nail. The cuticle should be pushed up gently because if we disrupt the sealed barrier infection may occur.
White half -moon on the nail plate which cannot be seen in each case. The lunula attaches the matrix and root tissues to the nail bed.
4. Nail bed (its visible part)
Pinky area between the lunula and the free edge. It lies beneath the nail and contains nerves and capillaries so it is a very sensitive point. Capillaries make the nail a pink colour. It is the pink area extending from the margin of lunula to the free edge. Just like the skin, the nail bed consists of two epithelial types, the dermis and the epidermis. The nail plate is closely attached to the nail bed ensuring its advanced growth. The dermis, which is the base layer of the epidermis, is attached to the phalanx-bones and it does not move, its upper surface is grooved. The lower part of the epidermis is attached to this, the ducts of which are fit into the stems of the dermis ensuring its advancing in a straight line.
5. Natural nail plate
Translucent, dead, visible keratinous plate.
6. Free edge
Free, unsuspended part of the nail plate which is separated from the nail bed with a definite curve, its free part runs above the fingertip (whitish coloured).
7. Posterior nail fold
A skin fold attached closely to the nail plate behind. It protects the nail matrix, it is about 5 mm wide. It is made up of two layers that are closely attached to each other. Its bottom layer is a cuticle that is pressesd on the plate but can be easily removed and only a part of which is visible, the rest is embedded under the posterior skin fold. Disruption of the sealed nail fold may lead to serious lesions caused by infection.
8. Lateral nail fold
Where the nail plate enters on both sides.
9. Anterior nail fold
Skin surface under the free edge that protects the nail bed (the edge of nail bed). The anterior nail fold acts as a „parting-point”. Soft skin layer that is situated on the point where the nail runs out of the nail bed.
Smile line is a glassy, thin, greyish band found between the nail plate and the proximal nail fold, the point where the nail plate above the nail bed touches the free edge.
Nail groove is a cutaneous slit surrounding the nail on both sides, nail wall is the cutaneous fold that is found above the nail groove.