Nail seminar


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Nail anatomy and physiology

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Nail seminar

  3. 3. INTRODUCTION  nail apparatus - strong, relatively inflexible, keratinous  protective covering for fingertip  allows precision and delicacy when picking up small objects
  4. 4. SHORT EMBRYOLOGY  primitive epidermis – 9 - 20th wks.  20 wk  matrix cells show postnatal-type cell division  differentiation and keratinization  nail plate begins to form and move distally  nail bed loses its granular layer at this stage.  36 wk: nail plate reaches the tip of the digit and is surrounded by prominent lateral nail folds and a well-formed cuticle.
  5. 5. NAIL BASIC STRUCTURE  1/4 nail is covered by the proximal nail fold  Lunula (half-moon, lunule)  Under proximal part of nail  most distal region of the matrix  most prominent on thumb & great toe  may be partly or completely concealed by the proximal nail fold in other digits  nail plate distal to lunula usually appears pink, due to its translucency, which allows the redness of the vascular nail bed to be seen through it.
  6. 6.  PROXIMAL NAIL FOLD  two epithelial surfaces, dorsal and ventral, at the junction of the two, the cuticle projects distally onto the nail surface.  LATERAL NAIL FOLDS  continuity with the skin on the sides of the digit laterally, and medially they are joined by the nail bed.  THE MATRIX  subdivided into dorsal (ventral aspect of the proximal nail fold), intermediate (germinal matrix or matrix) and ventral (nail bed) sections.  two distinct areas may be visible, THE PROXIMAL LUNULA AND THE LARGER PINK ZONE on seeing nail plate from above  On close examination, two further distal zones can often be identified , the distal yellowish-white margin and immediately proximal to this the onychodermal band
  7. 7. MICROSCOPIC ANATOMY  NAIL FOLDS  The proximal nail folds are similar in structure to the adjacent skin  devoid of dermatoglyphic markings and pilosebaceous glands.  From the distal area of the proximal nail fold the cuticle adheres to the upper surface of the nail plate  serves to protect the structures at the base of the nail, particularly the germinal matrix, from environmental insults
  8. 8.  NAIL MATRIX (INTERMEDIATE MATRIX)  Nail matrix produces the nail plate  The nail matrix contains melanocytes in the lowest three cell layers and these donate pigment to the keratinocytes.  there is presence of 6.5 melanocytes per millimetre of matrix basement membrane  Langerhans cells are detectable in the matrix by CD1a staining, and the matrix appears to contain basement membrane components
  9. 9.  NAIL BED  Nail bed consists of epidermis with underlying connective tissue closely apposed to the periosteum of the distal phalanx.  There is no subcutaneous fat in the nail bed  The nail bed epidermis is usually two or three cells thick  The nail bed dermal collagen is mainly orientated vertically, being directly attached to the phalangeal periosteum and the epidermal basal lamina.  Within the connective tissue network lie blood vessels, lymphatics, a fine network of elastic fibres and scattered fat cells; at the distal margin, eccrine sweat glands have been seen
  10. 10.  NAIL PLATE  The nail plate comprises three horizontal layers: a thin dorsal lamina, the thicker intermediate lamina and a ventral layer from the nail bed  The nail plate contains significant amounts of phospholipid, mainly in the dorsal and intermediate layers, which contributes to its flexibility.  The nail plate is rich in calcium, found as the phosphate in hydroxyapatite crystals  Calcium does not significantly contribute to the hardness of the nail
  11. 11.  NAIL KERATIN  Nail keratin analysis shows essentially the same fractions as in hair  amino acid analysis shows higher cysteine, glutamic acid and serine, and less tyrosine in nail compared with hair  normal nail demonstrates that the suprabasal keratin pair K1/K10 is found on both aspects of the proximal nail fold and to a lesser degree in the matrix. However, it is absent from the nail bed.  The nail bed contains keratin synthesized in normal basal layer epithelium, K5/K14, which is also found in nail matrix.  keratin pair K6/K16 are present in the nail bed but not in the germinal matrix
  12. 12. BLOOD SUPPLY OF NAIL  rich arterial blood supply to the nail bed and matrix derived from paired digital arteries, a large palmar and small dorsal digital artery on either side.  There are two main arterial arches (proximal and distal) supplying the nail bed and matrix, formed from anastomoses of the branches of the digital arteries.  Within the matrix, vessels are longitudinal with a helicoidal twisting..  There are many arteriovenous anastomoses beneath the nail— glomus bodies—which are concerned with heat regulation  Glomus bodies are important in maintaining acral circulation under cold conditions: arterioles constrict with cold but glomus bodies dilate.
  13. 13. Arterial supply of the distal finger.
  14. 14. NAIL GROWTH AND MORPHOLOGY  Cell kinetics  Measured by immunohistochemistry, autoradiography and direct measurement of matrix product (i.e. nail plate) by ultrasound ,micrometer or histology.  The rate of nail growth is about 3 mm/month for finger nails and about 1 mm/month for toe nails
  15. 15. NAIL MORPHOLOGY  The nail grows flat, rather than as a heaped-up keratinous mass  factors probably responsible to produce a relatively flat nail plate are  orientation of the matrix rete pegs and papillae  the direction of cell differentiation and moulding of the direction of nail growth between the proximal nail fold and distal phalanx.  Containment laterally within the lateral nail folds assists this orientation  the adherent nature of the nail bed
  18. 18. NAILS IN CHILDHOOD  In early childhood, the nail plate is relatively thin and may show temporary koilonychia  nails are also prone to terminal onychoschizia (lamellar splitting),most prominent on the sucked thumb.  Beau’s lines can be seen in up to 92% of normal infants between 8 and 9 weeks of age  A herringbone pattern is common in children and gradually diminishes with time, reflecting a gradual matrix maturation
  19. 19. NAILS IN OLD AGE  The whole subungual area in old age may show thickening of blood vessel walls with vascular elastic tissue fragmentation.  The nail plate becomes pallor, dull and opaque with advancing years  white nails similar to those seen in cirrhosis, uraemia and hypoalbuminaemia may be seen.
  20. 20. NAIL SIGNS AND SYSTEMIC DISEASE  ABNORMALITIES OF SHAPE  CLUBBING --  In clubbing there is increased transverse and longitudinal nail curvature with hypertrophy of the soft-tissue components of the digit pulp.  Hyperplasia of the fibrovascular tissue at the base of the nail also occurs.  Pathological associations of clubbing include --- inflammatory bowel disease, carcinoma of the bronchus and cirrhosis.  In forms associated with bronchiectasis or neoplasm, prominent inflammatory joint signs may also be seen, resulting in hypertrophic pulmonary osteoarthropathy
  21. 21. CLINICAL PICTURE OF CLUBBING Lovibond’s angle is found at the junction between the nail plate and the proximal nail fold, and is normally less than 160°. This is altered to over 180° in clubbing Curth’s angle at the distal interphalangeal joint is normally about 180°. This is diminished to less than 160° in clubbing
  22. 22.  Schamroth’s window is seen when the dorsal aspects of two fingers from opposite hands are opposed, revealing a window of light, bordered laterally by the Lovibond angles. As this angle is obliterated in clubbing, the window closes.  In some cases of bronchiectasis, a variant of clubbing, shell nail syndrome is seen.  Distugunished from clubbing by the presence of atrophy of underlying bone and nail bed
  23. 23. KOILONYCHIA  Greek: koilos, hollow; onyx, nail  In koilonchyia there is reverse curvature in the transverse and longitudinal axes giving a concave dorsal aspect to the nail  most prominent in the thumb or great toe.  common in infancy in toe nail  Its persistence may be associated with a deficiency of cysteine-rich keratin
  24. 24.  a familial pattern which may be autosomal Dominant may be seen in some families  Most common systemic association is with iron deficiency and haemochromatosis
  25. 25. PINCER NAIL  Also known as trumpet or involuted nail  Pincer nail describes a dystrophy where nail growth is pitched towards the midline, combined with increased transverse curvature.  There are 3 variants of pincer nail 1) In the inherited version there is often a gradient of involvement, radiating from the thumbs and big toes outwards, which progresses with time.
  26. 26. 2) the most common is in association with psoriasis, where the thumbs and big toes are the most likely to be affected, although the pattern is not as organised and symmetrical as that seen in the inherited version 3) The third variant is the individual nail which develops a pincer deformity. .
  27. 27. MACRONYCHIA AND MICRONYCHIA  Macronychia and micronychia are conditions where a nail is considered too large or too small in comparison with other nails  The nail disorder is usually associated with an abnormal digit, arising from underlying bony abnormalities such as local gigantism causing macronychia or megadactyly .  Also the basis of racket thumb, the most common form of benign, dominantly inherited macronychia
  28. 28. RACKET NAIL
  29. 29. ANONYCHIA  Anonychia is absence of all or part of one or several nails. It may be congenital, acquired or transient.  A mutation in the R-spondin 4 gene, which plays a part in Wnt signalling within the cell is responsible for congenital absence of nail  Acquired forms are due to scarring of the nail matrix. This can arise as a result of burns, surgery or trauma, or be due to inflammatory dermatoses such as lichen planus where the entire nail matrix is scarred and lost  The transient variant is due to nail shedding. This can occur due to an intense physiological or local inflammatory process,
  30. 30. ABNORMALITIES OF NAIL ATTACHMENT  Nail shedding Nails may be lost through different mechanisms 1) Complete loss of the nail plate due to proximal nail separation extending distally is called onychomadesis and is a progression of profound Beau’s lines
  31. 31. 2) Local dermatoses, such as the bullous disorders and paronychia, cause nail loss e.g. toxic epidermal necrolysis, lichen planus etc. 3) Trauma is a common cause of recurrent loss It is often associated with subungual haemorrhage
  32. 32. 4) Temporary loss has also been described due to drugs such as retinoids,cloxacillin and cephaloridine 5) Onychoptosis defluvium or alopecia unguium describes atraumatic,familial, non-inflammatory nail loss 6) Nail shedding can be part of an inherited structural defect, most obviously in epidermolysis bullosa 7) Nail degloving this refers to partial or total avulsion of the nail and surrounding tissue (perionychium).Typically,it appears as thimble-shaped nail shedding or total loss of the nail organ with soft tissue
  33. 33. DIFFERENT EXAMPLES OF SEPERATION OF NAIL ATTACHMENT ONYCHOLYSIS  Onycholysis is the distal or lateral separation of the nail from the nail bed  Psoriatic onycholysis can be considered the reference point for other forms of onycholysis where it is typically distal, with variable lateral involvement.  Areas of separation appear white or yellow due to air beneath the nail and sequestered debris, shed squames and glycoprotein exudate.  Isolated islands of onycholysis present as ‘oily spots’ or ‘salmon patches’ in the nail bed.
  34. 34.  Idiopathic onycholysis  This is a painless separation of the nail from its bed, which occurs without apparent cause. Overzealous manicure, frequent wetting and cosmetic ‘solvents’ may be the cause.  The condition usually starts at the tip of one or more nails and extends to involve the distal third of the nail bed.
  35. 35. Onycholysis: idiopathic type Fingernail in psoriasis
  36. 36.  Secondary onycholysis  Onycholysis due to other causes is secondary onycholysis. It may be localised or systemic  Psoriasis, fungal infections, dermatitis and trauma are among the most common. Onycholysis occurs in general medical conditions, including impaired peripheral circulation, hypothyroidism ,hyperthyroidism , hyperhidrosis, yellow nail syndrome and shell nail syndrome  Photo-onycholysis may occur during treatment with psoralens, demethylchlortetracycline and doxycycline
  37. 37. PTERYGIUM  The term ‘pterygium’ describes the winged appearance achieved when a central fibrotic band divides a nail proximally in two.  inflammatory destructive process precedes pterygium formation.  There is fusion between the nail fold and underlying nail bed and matrix.  The fibrotic band then obstructs normal nail growth.  It most typically develops in trauma or lichen planus and its variants, including idiopathic atrophy of the nail and graft- versus-host disease  It can also occur in leprosy and secondary purulent infection.
  38. 38.  Ventral Pterygium  Ventral pterygium or pterygium inversum unguis occurs on the distal undersurface of the nail  Causes include trauma, systemic sclerosis,Raynaud’s phenomenon, lupus erythematosus, familial and infective .
  39. 39. Subungual hyperkeratosis  entails hyperkeratosis of the nail bed and hyponychium  Nail plate thickening is common. Dry, white or yellow hyperkeratosis may crumble away from the overhanging nail Hyperkeratosis may extend onto the digit pulp.  Features of onychomycosis and wart virus infection (mainly toes) or psoriasis, pityriasis rubra pilaris and eczema (mainly fingers) are found  The nail bed is an epithelium of low proliferative turnover. Any disease process that affects it is likely to result in an excess of squamous debris. The overlying nail prevents simple loss. The initial outcome is compaction of debris into layers of subungual hyperkeratosis.  Focal subungual keratoses seen with Darier’s disease, and keratotic debris beneath the nail in Norwegian (crusted).
  40. 40. CHANGES IN NAIL SURFACE Longitudinal grooves  Longitudinal grooves may run all or part of the length of the nail in the longitudinal axis  The median canaliform dystrophy of Heller is the most distinctive form in this  The nail is split, usually in the midline, with a fir- tree-like appearance of ridges angled backwards.  The thumbs are most commonly affected and the involvement may be symmetrical.
  41. 41. TRANSVERSE GROOVES AND BEAU’S LINES  Transverse grooves may be full or partial thickness through the nail.  When they are endogenous they have an arcuate margin matching the lunula.  If exogenous, such as those due to manicure the margin may match the proximal nail fold and the grooves may be multiple as in washboard nails.
  42. 42. BEAU’S LINES When the transverse groove’s are due to endogenous cause, the groove is better known as beau’s lines
  43. 43. PITTING  Pitting presents as punctate erosions in the nail surface  The individual pits of psoriasis are said to be less regular  An isolated large pit may produce a localized full thickness defect in the nail plate termed elkonyxis, which is found in Reiter’s disease, psoriasis and following trauma
  44. 44. TRACHYONYCHIA  Trachyonychia presents as a rough surface affecting all of the nail plate and up to 20 nails  The original French term was ‘sand-blasted nails’, which evokes the main clinical feature of a grey, roughened surface  mainly associated with alopecia areata, psoriasis and lichen planus
  45. 45. ONYCHOSCHIZIA  Onychoschizia is also known as lamellar dystrophy and is characterized by transverse splitting into layers at or near the free edge  It is seldom associated with any systemic disorder, although it has been reported with polycythaemia, human immuno-deficiency virus (HIV) infection and glucagonoma
  46. 46. CHANGES IN COLOUR  Alteration in nail colour may occur because of changes affecting the dorsal nail surface, the substance of the nail plate, the undersurface of the nail or the nail bed.  Exogenous pigment  Exogenous pigment on the upper surface is easy to demonstrate by scraping the nail. If the proximal margin of the pigment is an arc matching the proximal nail fold, this is a further clue confirming an exogenous source.
  47. 47. NAIL PLATE CHANGES  The nail plate can be changed by the addition of pigment or the alteration of the normal cellular and intercellular organization such that there is loss of normal lucency.  Normal Pigment is typically added in the form of melanin produced by matrix melanocytes during nail formation. This produces a brown longitudinal streak the entire length of the nail.  The incorporation of heavy metals and some drugs into the nail via the matrix can also produce altered nail plate colour, such as the grey colour associated with silver.  The disruption of normal nail plate formation by disease, chemotherapy, poisons or trauma can result in waves of parakeratotic nail cells or small splits between cells within the nail.  In fungal infection discoloration may start distolaterally rather than via the matrix.
  48. 48. NAIL BED CHANGES  Normally there is generalized vascular changes in the nail bed, but localized changes, as seen with nail bed tumours.  Subungual hyperkeratosis or the incorporation of drugs (antimalarials, phenothiazines) may also change the apparent colour of the nail.  Splinter haemorrhages, representing ruptured nail bed vessels, deposit haemoglobin on the undersurface of the nail, which grows out.  Cyanosis makes the nail bed blue and carbon monoxide poisoning makes it bright red.
  49. 49. LEUKONYCHIA  White discoloration of the nail attributable to matrix dysfunction is known as leukonychia.  In an inherited form called total leukonychia, all nails are milky porcelain white.  In subtotal leukonychia,  the proximal two-thirds are white, becoming pink distally.  This is attributed to a delay in keratin maturation  Transverse leukonychia (Mees’ line) reflects a systemic disorder , such as chemotherapy or poisoning
  50. 50. APPARENT LEUKONYCHIA  In apparent leukonychia,  changes in the nail bed are responsible for the white appearance.  Nail bed pallor may be a non-specific sign of anaemia, oedema or vascular impairment.
  51. 51. TERRY’S NAIL  This is white proximally and normal distally  Seen in cirrhosis, congestive cardiac failure and adult-onset diabetes mellitus.  Nail bed biopsy reveals only mild changes of increased vascularity.  Terry’s nail is similar to half-and-half nails where,  there is a proximal white zone and distal (20–60%) brownish sharp demarcation,  the histology of half and half nail suggests an increase of vessel wall thickness and melanin deposition.  seen in 9–50% of patients with chronic renal failure and after chemotherapy
  52. 52. MUEHRCKE’S PAIRED WHITE BANDS  These bands are parallel to the lunula in the nail bed, with pink between two white lines.  They are commonly associated with hypoalbuminaemia  the correction of hypoalbuminaemia by albumin infusion can reverse the sign.
  53. 53. COLOUR CHANGES DUE TO DRUGS  Yellowing of the nail is a rare occurrence in prolonged tetracycline therapy, which can also produce a pattern of dark distal photo-onycholysis associated with photosensitivity BLUE MEPACRINE BLUE- BLACK CHLOROQUI NE DARK BLUE DRUG ERUPTION HYPERPIG MENTATIO N DOXORUBICI N IN CHILDREN
  54. 54. YELLOW NAIL SYNDROME •The nails in yellow nail syndrome are yellow due to thickening, •a tinge of green suggets secondary infection. •The lunula is obscured •increased transverse and longitudinal curvature •loss of cuticle •chronic paronychia with onycholysis and transverse ridging may occur • The condition usually presents in adults
  55. 55. YELLOW NAIL SYNDROME  An autosomal dominnant inheritance is suspected  lymphoedema at one or more sites may accomapany  respiratory or nasal sinus disease may present  Also occur in d-penicillamine therapy and nephrotic syndrome ,hypothyroidism & AIDS  Attempted treatments include oral and topical vitamin E, oral zinc
  56. 56. LONGITUDINAL ERYTHRONYCHIA •It is a longitudinal red streak in the nail •Forms a strip where the nail bed is less compressed by the overlying nail so that blood pools • color is more easily seen because the nail is thinner in this line. •Splinter hemorrhages may lie longitudinally •Seen with lichen planus & darrier’s disease , acrokeratosis verruciformis
  57. 57. ONYCHOPAPILLOMA  Describe the isolated, benign warty distal nail bed lesions  term coined by baran  Can be associated with longitudinal erythronychia  The papilloma is a secondary element, given that it is found distally in the nail bed while the cause lies proximally within the matrix. .