Simple Nail Designs For Short Nails Biography
(Source google.com)
The nail wall (vallum unguis) is the cutaneous fold overlapping the
sides and proximal end of the nail. The lateral margin (margo lateralis) lies
beneath the nail wall on the sides of the nail and the nail groove or fold
(sulcus matricis unguis) are the cutaneous slits into which the lateral margins
are embedded. The paronychium is the border tissue around the nail and
paronychia is an infection in this area. A healthy finger nail has the function
of protecting the distal phalanx, the fingertip, and the surrounding soft
tissues from injuries. It also serves to enhance precise delicate movements of
the distal digits through counter-pressure exerted on the pulp of the finger.
The nail then acts as a counterforce when the end of the finger touches an
object, thereby enhancing the sensitivity of the fingertip, even though there
are no nerve endings in the nail itself. Finally, the nail functions as a tool,
enabling for instance a so-called "extended precision grip" (e.g.
pulling out a splinter in one's finger), and certain cutting or scraping
actions. The growing part of the nail is under the skin at the nail's proximal
end under the epidermis, which is the only living part of a nail. In mammals,
the length and growth rate of nails is related to the length of the terminal
phalanges (outermost finger bones). Thus, in humans, the nail of the index
finger grows faster than that of the little finger; and fingernails grow up to
four times faster than toenails. In humans, nails grow at an average rate of 3
mm (0.12 in) a month. Fingernails require three to six months to regrow
completely, and toenails require 12 to 18 months. Actual growth rate is
dependent upon age, sex, season, exercise level, diet, and hereditary factors.
Nails grow faster in the summer than in any other season. Contrary to popular
belief, nails do not continue to grow after death; the skin dehydrates and
tightens, making the nails (and hair) appear to grow.
The matrix, sometimes called the matrix unguis, keratogenous membrane,
nail matrix, or onychostroma, is the tissue (or germinal matrix) which the nail
protects. It is the part of the nail bed that is beneath the nail and contains
nerves, lymph and blood vessels. The matrix is responsible for producing cells
that become the nail plate. The width and thickness of the nail plate is
determined by the size, length, and thickness of the matrix, while the shape of
the fingertip itself shows if the nail plate is flat, arched or hooked. The
matrix will continue to grow as long as it receives nutrition and remains in a
healthy condition. As new nail plate cells are made, they push older nail plate
cells forward; and in this way older cells become compressed, flat, and
translucent. This makes the capillaries in the nail bed below visible,
resulting in a pink color. The lunula ("small moon") is the visible
part of the matrix, the whitish crescent-shaped base of the visible nail. The
lunula can best be seen in the thumb and may not be visible in the little
finger. The nail bed is the skin beneath the nail plate. Like all skin, it is
made of two types of tissues: the deeper dermis, the living tissue which
includes capillaries and glands, and the epidermis, the layer just beneath
the nail plate, which moves toward the finger tip with the plate. The epidermis
is attached to the dermis by tiny longitudinal "grooves" called
matrix crests (cristae matricis unguis). In old age, the nail plate becomes
thinner so that these grooves become more visible.
The nail sinus (sinus unguis) is where the nail root is; i.e. the base
of the nail underneath the skin. It originates from the actively growing tissue
below, the matrix. The nail plate (corpus unguis) is the hard part of the nail,
made of translucent keratin protein. Several layers of dead, compacted cells
cause the nail to be strong but flexible. Its (transverse) shape is determined
by the form of the underlying bone. In common usage, the word nail often refers
to this part only. The free margin (margo liber) or distal edge is the anterior
margin of the nail plate corresponding to the abrasive or cutting edge of the
nail. The hyponychium (informally known as the "quick") is the
epithelium located beneath the nail plate at the junction between the free edge
and the skin of the fingertip. It forms a seal that protects the nail bed. The
onychodermal band is the seal between the nail plate and the hyponychium. It is
just under the free edge, in that portion of the nail where the nail bed ends
and can be recognized by its glassy, greyish colour (in fair-skinned people).
It is not visible in some individuals while it is highly prominent on others.
The eponychium is the small band of epithelium that extends from the posterior
nail wall onto the base of the nail. Often and erroneously[contradictory]
called the "proximal fold" or "cuticle", the eponychium is
the end of the proximal fold that folds back upon itself to shed an epidermal
layer of skin onto the newly formed nail plate. This layer of non-living,
almost invisible skin is the cuticle that "rides out" on the surface
of the nail plate. Together, the eponychium and the cuticle form a protective
seal. The cuticle on the nail plate is dead cells and is often removed during
manicure, but the eponychium is living cells and should not be touched. The
perionyx is the projecting edge of the eponychium covering the proximal strip
of the lunula.
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