Nail

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Anatomy

In anatomy, a nail is a horny epidermal derivative that covers the dorsal tip of the fingers and toes of humans and most primates, consisting of a flattened, slightly curved translucent plate of the protein keratin, which is formed largely from dividing cells in the base, is attached to an slides over a nail bed, and has a free edge. In humans, it is the largest skin appendage (Haneke 2006), homologous to vertebrate claws and hooves, and made of the same protein found in hair, skin, and horns.

scratch pick up objects

decoration of toenails and fingernails for aesthetic purposes dates at least as far back as Ancient Egypt (


Parts of the nail

Fingernails
Toenails

Anatomically fingernails and toenails, which are made of a tough protein called keratin and are produced from living skin cells in the fingers and toes, are made up of many different parts:

  • The free edge is the part of the nail that extends past the finger, beyond the nail plate. There are no nerve endings in the nail - this is the growing part of the nail still under the skin at the nail's proximal end.
  • eponychium or cuticle, is the fold of skin at the proximal end of the nail.
  • paronychium 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 end of the nail.
  • nail plate is the hard and translucent portion, composed of keratin.
  • nail bed is the adherent connective tissue that underlies the nail, often colloquially referred to as the "quick."
  • lunula is the crescent shaped whitish area of the nail bed (when visible)
  • nail fold a fold of hard skin overlapping the base and sides of a fingernail or toenail.

In common usage the word nail usually refers to the nail plate only.


Long, manicured nails are a fashion statement.

Nails grow at an average rate of 3 millimetres a month [1] Fingernails require 3 to 6 months to regrow completely. Toenails require 12 to 18 months. Actual growth rate is dependent upon age, season, exercise level, and hereditary factors. And contrary to popular belief, they do not continue to grow after death, the skin dehydrates and tightens giving the illusion that the nails grow, the same goes for hair.

This growth record can show the history of recent health and physiological imbalances, and has been used as a diagnostic tool since ancient times.[2] Major illness will cause a deep groove to form across the nails. Miscoloration, thinning, thickening, brittleness, splitting, grooves, Mees' lines, small white spots, receded lunula, clubbing (convex), flatness, spooning (concave) can indicate illness in other areas of the body, nutrient deficiencies, drug reaction or poisoning, or merely local injury. Nails can also become thickened (onychogryphosis), loosened (onycholysis), infected with fungus (onychomycosis) or degenerative (onychodystrophy); for further information see nail diseases. +

Health and care

Nails can dry out, just like skin. They can also be infected: toe infections, for instance, can be caused or exacerbated by dirty socks, specific types of aggressive exercise, tight footwear and walking unprotected in an unclean environment.[citation needed]

Manicures and pedicures are health and cosmetic procedures to groom, trim, and paint the nails and manage callouses. They require various tools such as cuticle scissors, nail scissors, nail clippers, and nail files.

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.[3] 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.

Biting

Biting the nails often indicates internal tension, stress, boredom, hunger, or it may simply be a habit.

Nail biting can result in the transportation of germs that are buried under the surface of the nail into the mouth. It may also cause excessive or abnormal wear of tooth enamel[citation needed].

Culture

Empress Dowager Cixi displays long fingernails which reflect her high position in Qing China.

In western culture, long nails are a symbol of femininity, while short nails are a symbol of masculinity. Nail decoration is usually limited to females.

In some Asian cultures men may also grow long fingernails, or only the nail on the little finger, to show that they do not do much manual labor, but instead work in an office setting.

In the 19th century in the Balkans, white-collar workers, such as clerks, grew their fingernails long to distinguish them from people in lower classes who worked with their hands.[1]

Some guitar players, notably classical and fingerstyle players, will purposely grow long nails on the hand they use to pluck the strings. Their longer nails serve as small, easily-maneuverable guitar picks. For some serious musicians, daily nail care can become a mark of pride and dedication.

In comparison, pianists must keep their nails trimmed short to avoid clicking noises on the keys and avoid dangerous situations where in fast passages the nail may be caught under a key and rip off, and most string players, such as violinists and guitarists, must keep at least the nails on their fretting hand short to allow the strings to be fingered correctly.

Fashion

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

Painting the nails with nail polish (also known as nail lacquer) is a common practice dating back to at least 3000 B.C.E.

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 (paramedics) often use the fingernail beds as a cursory indicator of distal tissue perfusion of individuals who may be in shock. However, this test is now accepted as reliable in young children only.[citation needed]

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.[citation needed]

See also

  • Leukonychia
  • Nail disease
  • Hangnail

References
ISBN links support NWE through referral fees

  1. A History of Western Society. John McKay.
  • Blakemore, C., and S. Jennett. 2001. The Oxford Companion to the Body. New York: Oxford University Press. ISBN 019852403X.
  • Haneke, E. 2006. Onychocosmeceuticals. Journal of Cosmetic Dermatology 5(1): 95-100.
  • Levit, E. K., and R. E. Boissy, R. E. 2001. Chapter 6. Basic science of the nail unit. In R. K. Freinkel, and D. T. Woodley. The Biology of the Skin. New York: Parthenon Pub. Group. ISBN 1850700060.
  • Haneke E (2006). Surgical anatomy of the nail apparatus.. Dermatol Clin 24 (3): 291-6. PMID 16798426.
  1. ^  Toenail Definition - Medicine.net
  2. ^  American Academy of Dermatology - Nail Health
  3. ^  Nails Guide - Nail Health


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