Nail (anatomy)

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Nail (anatomy)

A nail is a horn

Horn (anatomy)

A horn is a pointed projection of the skin on the head of various mammals, consisting of a covering of horn surrounding a core of living bone....
-like structure at the end of an animal's finger

Finger

A finger is a type of digit , an organ of manipulation and sensation found in the hands of humans and other primates.Normally humans have five digits, termed phalanges, on each hand ....
or toe

Toe

Toes are the Digit s of the foot of an animal. Many animal species such as cats walk on their toes, and are described as being digitigrade....
. See also claw

Claw

A claw is a curved, pointed appendage, found at the end of a toe or finger in most mammals, birds, and some reptiles. Somewhat similar fine hooked structures are found in arthropods such as beetles and spiders, at the end of the leg or Arthropod leg for gripping a surface as the creature walks....
.

omically fingernails and toenails are made of a tough protein

Protein

Proteins are organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid Residue ....
called keratin

Keratin

Keratins are a family of fibrous protein; tough and insoluble, they form the hard but mineral structures found in reptiles, birds, amphibians and mammals....
and have many different parts:

Nails act 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.

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Encyclopedia

A nail is a horn

Horn (anatomy)

Finger

A finger is a type of digit , an organ of manipulation and sensation found in the hands of humans and other primates.Normally humans have five digits, termed phalanges, on each hand ....
or toe

Toe

Toes are the Digit s of the foot of an animal. Many animal species such as cats walk on their toes, and are described as being digitigrade....
. See also claw

Claw

Parts of the nail

Anatomically fingernails and toenails are made of a tough protein

Protein

Keratin

Keratins are a family of fibrous protein; tough and insoluble, they form the hard but mineral structures found in reptiles, birds, amphibians and mammals....
and have many different parts:

eponychium
Eponychium

In human anatomy, the eponychium or cuticle is the thickened layer of skin surrounding nail . Beneath the cuticle is a thin layer of a membrane known as the pterygium....
or cuticle
Cuticle

In biology, a cuticle or cuticula is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or part of an organism, that provide protection....
, is the fold of skin at the proximal end of the nail.
paronychium
Paronychium

Paronychium or the "lateral nail fold" is the term for the soft tissue surrounding the border of the fingernail or toenail. ...
is the fold of skin on the sides of the nail.
hyponychium is the attachment between the skin of the finger or toe and the distal
Anatomical terms of location

Standard anatomical terms of location are employed in sciences dealing with the anatomy of animals to avoid ambiguities which might otherwise arise....
end of the nail.
nail plate is the hard and translucent portion, composed of keratin
Keratin

Keratins are a family of fibrous protein; tough and insoluble, they form the hard but mineral structures found in reptiles, birds, amphibians and mammals....
.
nail bed is the adherent connective tissue that underlies the nail, often referred to as the "quick."
lunula
Lunula (anatomy)

The lunula, or lunulae , is the crescent-shaped whitish area of the bed of a fingernail or toenail. The lunula is the visible part of the nail matrix ....
is the crescent shaped whitish area of the nail bed (when visible)
nail fold is a fold of hard skin overlapping the base and sides of a fingernail or toenail.
the free edge is the part of the nail that extends past the finger, beyond the nail plate.

Nails act 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. The growing part of the nail is the part still under the skin at the nail's proximal end. The average thickness of this portion of the nail is .017 inches or 0.43 millimetres. In common usage the word nail often refers to the nail plate only.

Nails grow at an average rate of 3 millimeters a month. Fingernails require 3 to 6 months to regrow completely, and toenails require 12 to 18 months. Although it is widely believed that toenails do not grow back, this is not true. Actual growth rate is dependent upon age, gender, season, exercise level, diet, and hereditary factors. 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.

This growth record can show the history of recent health and physiological imbalances, and has been used as a diagnostic tool since ancient times. Major illness will cause a deep transverse groove

Beau's lines

Beau's lines are deep grooved lines that run from side to side on the nail . They may look like indentations or ridges in the nail plate.There are several reasons that humans get Beau's lines....
to form across the nails. Discoloration, thinning, thickening, brittleness, splitting, grooves, Mees' lines

Mees' lines

Mees' lines or Aldrich-Mees' lines are lines of discoloration across the Nail of the fingers and toes....
, small white spots

Leukonychia

Leukonychia is a medical term for white discoloration appearing on nail . It is derived from the Greek words Leuko white and Onyx nail....
, receded lunula, clubbing

Clubbing

In medicine, clubbing, finger clubbing, or digital clubbing is a deformity of the fingers and Nail s that is associated with a number of diseases, mostly of the heart disease and lung disease....
(convex), flatness, spooning (concave) can indicate illness in other areas of the body, nutrient deficiencies, drug reaction or poison

Poison

In the context of biology, poisons are Chemical substance that can cause disturbances to organisms, usually by chemical reaction or other activity on the molecular scale, when a sufficient quantity is absorbed by an organism....
ing, or merely local injury. Nails can also become thickened (onychogryposis), loosened (onycholysis

Onycholysis

Onycholysis refers to the detachment of the nail from the nail bed, starting at its distal and/or lateral attachment.References...
), infected with fungus (onychomycosis

Onychomycosis

Onychomycosis means fungus dermatophytosis of the Nail . It is the most common disease of the nails and constitutes about a half of all nail abnormalities....
) or degenerate (onychodystrophy); for further information see nail disease

Nail disease

Nail diseases are distinct from diseases of the skin. Although nail s are a skin appendage, they have their own signs and symptoms which may relate to other medical conditions....
s.

Health and care

Nails can dry out, just like skin

Skin

The skin is the outer covering of the body, also known as the epidermis. It is the largest organ of the integumentary system made up of multiple layers of epithelial biological tissue, and guards the underlying muscles, bones, ligaments and organ s....
. They can also peel, break and be infected. Toe infections, for instance, can be caused or exacerbated by dirty sock

Sock

A sock is a knitted or woven type of hosiery garment for enclosing the human foot. Socks are designed to:* ease chafing between the foot and footwear...
s, specific types of aggressive exercise, tight footwear

Footwear

Footwear consists of garments worn on the foot, for protective clothing against the environment, and adornment. Socks and other hosiery are worn between the feet and the footwear, except for Sandal s and flip flops ....
and walking unprotected in an unclean environment.

Manicure

Manicure

A manicure is a cosmetic beauty treatment for the fingernails and hands performed either at home or in a nail salon by a nail technician. A manicure treatment can be just for the hands or nails, or can be for both....
s and pedicure

Pedicure

A pedicure is a way to improve the appearance of the foot and their nail s. It provides a similar service as a manicure. The word pedicure comes from the Latin words pedis, which means of the foot, and cura, which means care....
s are health and cosmetic procedures to groom, trim, and paint the nails and manage calluses. They require various tools such as cuticle scissors, nail scissors, nail clipper

Nail clipper

A nail clipper is a machine device used to trim fingernails and toenails. Nail clippers are usually made of metal. Two common varieties are the plier type and the lever type....
s, and nail file

Nail file

A nail file is a tool used to gently grind down and shape the edges of Nail . They are often used in manicures and pedicures after the nail has been trimmed using appropriate nail clippers....
s. Artificial nails

Artificial nails

Artificial nails, also known as fake nails, fashion nails, nail enhancements, or nail extensions, are coverings placed over fingernails as fashion accessories....
can also be appended onto real nails for cosmetic purposes.

Nail tools used by different people may transmit infections. Regarding nail tools such as files, "If they're used on different people, these tools may spread nail fungi, staph bacteria or viruses", warns Rick Lopes, a spokesperson for the California Board of Barbering and Cosmetology. In fact, over 100 bacterial skin infections in 2000 were traced to footbaths in nail salons. To avoid this, new improved contactless tools can be used, for example, gel and cream cuticle removers instead of cuticle scissors.

Fashion

Someone whose occupation is to cut any type of nail, apply artificial nails and care for nails is sometimes called a nail technician. The place where a nail technician works may be called a nail salon or nail shop (also "nailshop").

Painting the nails with nail polish

Nail polish

Nail polish or nail varnish is a lacquer that is applied to the nail s of both the fingers and toes, usually cosmetically, but also as protection for the nails....
(also known as nail lacquer) is a common practice dating back to at least 3000 BCE.

Ornamented fake nails are sometimes used to display designs, such as stars or sparkles, on nails. They are also used to make nails look longer.

Medical test

Health care and pre-hospital care providers (EMTs or paramedics) often use the fingernail beds as a cursory indicator of distal tissue perfusion of individuals who may be dehydrated

Dehydration

Dehydration is the removal of water from an object. In Physiology terms, it entails a relative deficiency of water molecules in relation to other dissolved solutes....
or in shock. However, this test is not considered reliable in adults. This is known as the CRT or blanch test

Capillary refill

Capillary refill is the rate at which blood refills empty capillaries. It can be measured by pressing a fingernail until it turns white, and taking note of the time needed for colour to return once the nail is released....
.

Procedure: briefly depress the fingernail bed gently with a finger. This will briefly turn the nailbed white; the normal pink colour should be restored within a second or two. Delayed return to pink colour can be an indicator of certain shock states such as hypovolemia

Hypovolemia

In physiology and medicine, hypovolemia is a state of decreased blood volume; more specifically, decrease in volume of blood plasma. Volumetric thirst can be caused by a number of things including bleeding and diarrhea....