Tırnak Anatomisi,fizyolojisi-hastalıkları - Nail Anatomy-Parts of the Nail

Tırnak anatomisi,fizyolojisi-hastalıkları - Nail anatomy-Parts of the nail







İnsanda ve bazı hayvanlarda parmak ucunun üst bölümünü kaplayan sert ve boynuzsu tabaka Hayvanlarda, parmak ucunda boynuzsu oluşumlara ancak sürüngenler, kuşlar ve memeliler gibi üst yapılı omurgalılarda rastlanır Bunlar hemen her zaman pençe biçimindedir
Toynaklılarda bu boynuzsu oluşumlar, son derece gelişmişlerdir ve parmak kemiğinin uç bölümünü tümüyle çevrelerler Yassı tırnaklarsa yalnızca primatlarda görülür,
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Parts of the nail
Anatomically fingernails and toenails are made of a tough protein called keratin and have 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
Balba (free edge) is the front white part of the nail (Alba latin for White)
In common usage the word nail usually refers to the nail plate only
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, gender, season, exercise level, 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 to form across the nails Discoloration, 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

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