Normal Nail Anatomy, Normal Nail Histology, and Common Reaction Patterns

  • Aldo González-Serva


The human nail, the horny covering of the upper surface of the tip of each finger and toe, is a set of complex structures that can most accurately be called the nail unit. The visible nail plate is the ultimate product of the continuous pathway of maturation that occurs in this very active, specialized keratinizing unit. It is mainly through observations of this plate that patient and clinician become aware of the presence of disease in the unit as a whole. However, it is important to understand the functional and structural organization of the deeper, concealed components of the system, which account for the external findings clinically seen in the nails. This chapter deals with those components that are responsible for development of a normal nail plate. For the most part, morphologic components are discussed, but physiologic aspects of nail growth are also included.


Histology Functional histology Flat nail plate Thin nail plate Pathologic signs of nail diseases Eczema and ungual bacteriosis as new microscopic players Melanin mapping of the nail plate Nail erythrasma Nail gout 


  1. 1.
    González-Serva A. Anatomia macro- y microscópica de la uña (Macro- and microscopic anatomy of the nail). Monografías Dermatología (Spain) [Monogr Dermatol]: Patol Uña (I). Director of This Monograph: Dr. F. Camacho. 1991;IV(5):256–68.Google Scholar
  2. 2.
    Zaias N. The nail in health and disease. Jamaica: SP Medical and Scientific Books; 1980.Google Scholar
  3. 3.
    Thompson DAW. On growth and form. Cambridge: Cambridge University Press; 2014.Google Scholar
  4. 4.
    Norton LA. Incorporation of thymidine-methyl-H3 and glycine-2-H3 in the nail matrix and bed of humans. J Invest Dermatol. 1971;56(1):61–8.PubMedGoogle Scholar
  5. 5.
    Zaias N. The regeneration of the primate nail studies of the squirrel monkey, Ssaimiri. J Invest Dermatol. 1965;44:107–13.PubMedGoogle Scholar
  6. 6.
    Zaias N. The movement of the nail bed. J Invest Dermatol. 1967;48(4):402–3.PubMedGoogle Scholar
  7. 7.
    Zaias N, Alvarez J. The formation of the primate nail plate. An autoradiographic study in squirrel monkey. J Invest Dermatol. 1968;51(2):120–36.PubMedGoogle Scholar
  8. 8.
    Chapman RE. Hair, wool, quill, nail, claw, hoof, and horn. Biology of the integument. In: Matoltsy A, Bereiter-Hahn J, Richards KS, editors. Vertebrates, vol. 2. New York: Springer-Verlag; 1986.Google Scholar
  9. 9.
    Barron JN. The structure and function of the skin of the hand. Hand. 1970;2(2):93–6.PubMedGoogle Scholar
  10. 10.
    de Berker D. Nail anatomy. Clin Dermatol. 2013;31(5):509–15.PubMedGoogle Scholar
  11. 11.
    Haneke E. Anatomy of the nail unit and the nail biopsy. Semin Cutan Med Surg. 2015;34(2):95–100.PubMedGoogle Scholar
  12. 12.
    Samman PD. Anatomy and physiology. In: Fenton D, Samman PD, editors. The nails in disease. Chicago: Year Book; 1986.Google Scholar
  13. 13.
    Achten G. L’ongle normal et pathologique. Dermatologica. 1963;126:229.PubMedGoogle Scholar
  14. 14.
    Zook EG. Anatomy and physiology of the perionychium. Hand Clin. 1990;6(1):1–7.PubMedGoogle Scholar
  15. 15.
    Zook EG, Van Beek AL, Russell RC, Beatty ME. Anatomy and physiology of the perionychium: a review of the literature and anatomic study. J Hand Surg Am. 1980;5(6):528–36.PubMedGoogle Scholar
  16. 16.
    Park JH, Lee DY. CD10 is expressed in nail mesenchyme (onychodermis) containing onychofibroblasts of the adult nail unit. Clin Exp Dermatol. 2012;37(6):685–6.PubMedGoogle Scholar
  17. 17.
    Park JH, Lee DY, Ha SY, Jang KT, Kwon GY, Lee KH, Shim JS. The concept of onychodermis (specialized nail mesenchyme) is applicable in normal adult nail unit. Ann Dermatol. 2017;29(2):234–6.PubMedPubMedCentralGoogle Scholar
  18. 18.
    Perrin C. The nail dermis: from microanatomy to constitutive modelling. Histopathology. 2015;66(6):864–72.PubMedGoogle Scholar
  19. 19.
    González-Serva A. Onycholemmal keratinization: ensheathing and fastening of the nail plate (abstract). J Invest Dermatol. 1992;98:582.Google Scholar
  20. 20.
    De Berker D, Mawhinney B, Sviland L. Quantification of regional matrix nail production. Br J Dermatol. 1996;134(6):1083–6.PubMedGoogle Scholar
  21. 21.
    Johnson M, Shuster S. Continuous formation of nail along the bed. Br J Dermatol. 1993;128(3):277–80.PubMedGoogle Scholar
  22. 22.
    Lewis BL. Microscopic studies of fetal and mature nail and surrounding soft tissue. AMA Arch Derm Syphilol. 1954;70(6):733–47.PubMedGoogle Scholar
  23. 23.
    Zaias N. Embryology of the human nail. Arch Dermatol. 1963;87:37–53.PubMedGoogle Scholar
  24. 24.
    Hashimoto K, Gross BG, Nelson R, Lever WF. The ultrastructure of the skin of human embryos. 3. The formation of the nail in 16–18 weeks old embryos. J Invest Dermatol. 1966;47(3):205–17.PubMedGoogle Scholar
  25. 25.
    Sinclair RD, Wojnarowska F, Leigh IM, Dawber RP. The basement membrane zone of the nail. Br J Dermatol. 1994;131(4):499–505.PubMedGoogle Scholar
  26. 26.
    Jerasutus S. Histology and embryology of the nail unit. Histopathology of nail diseases. In: D CI, Scher RK, editors. Nail therapy. Philadelphia: WB Saunders; 1990.Google Scholar
  27. 27.
    Kouskoukis CE, Scher RK, Ackerman AB. The problem of features of lichen simplex chronicus complicating the histology of diseases of the nail. Am J Dermatopathol. 1984;6(1):45–9.PubMedGoogle Scholar
  28. 28.
    Ditre CM, Howe NR. Surgical anatomy of the nail unit. J Dermatol Surg Oncol. 1992;18(8):665–71.PubMedGoogle Scholar
  29. 29.
    Dykyj D. Anatomy of the nail. Clin Podiatr Med Surg. 1989;6(2):215–28.PubMedGoogle Scholar
  30. 30.
    Cohen PR. The lunula. J Am Acad Dermatol. 1996;34(6):943–53. quiz 954–946PubMedGoogle Scholar
  31. 31.
    Terry R. Red half-moons in cardiac failure. Lancet. 1954a;267(6843):842–4.PubMedGoogle Scholar
  32. 32.
    Terry R. White nails in hepatic cirrhosis. Lancet. 1954b;266(6815):757–9.PubMedGoogle Scholar
  33. 33.
    Monash S. Normal pigmentation in the nails of the Negro. Arch Dermatol Syphilol. 1932;25:876.Google Scholar
  34. 34.
    Higashi N. Melanocytes of nail matrix and nail pigmentation. Arch Dermatol. 1968;97(5):570–4.PubMedGoogle Scholar
  35. 35.
    Higashi N, Saito T. Horizontal distribution of the dopa-positive melanocytes in the nail matrix. J Invest Dermatol. 1969;53(2):163–5.PubMedGoogle Scholar
  36. 36.
    Kazi R, Moghaddam S, Chu P, Marghoob AA. Histologic evidence of melanocytes isolated to the nail matrix. JAMA Dermatol. 2016;152(5):573–5.PubMedGoogle Scholar
  37. 37.
    Perrin C, Michiels JF, Pisani A, Ortonne JP. Anatomic distribution of melanocytes in normal nail unit: an immunohistochemical investigation. Am J Dermatopathol. 1997;19(5):462–7.PubMedGoogle Scholar
  38. 38.
    Leyden JJ, Spott DA, Goldschmidt H. Diffuse and banded melanin pigmentation in nails. Arch Dermatol. 1972;105(4):548–50.PubMedGoogle Scholar
  39. 39.
    Stone OJ, Mullins JF. The distal course of nail matrix hemorrhage. Arch Dermatol. 1963;88:186–7.PubMedGoogle Scholar
  40. 40.
    Sonnex TS, Griffiths WA, Nicol WJ. The nature and significance of the transverse white band of human nails. Semin Dermatol. 1991;10(1):12–6.PubMedGoogle Scholar
  41. 41.
    Terry RB. The onychodermal band in health and disease. Lancet. 1955;268(6856):179–81.PubMedGoogle Scholar
  42. 42.
    Lewin K. The normal finger nail. Br J Dermatol. 1965;77(8):421–30.PubMedGoogle Scholar
  43. 43.
    Branca A. Notes sur la structure de l’ongle. Ann Dermatol Syphiligr. 1910;1:353.Google Scholar
  44. 44.
    Parrinello JF, Japour CJ, Dykyj D. Incurvated nail. Does the phalanx determine nail plate shape? J Am Podiatr Med Assoc. 1995;85(11):696–8.PubMedGoogle Scholar
  45. 45.
    Germann H, Barran W, Plewig G. Morphology of corneocytes from human nail plates. J Invest Dermatol. 1980;74(3):115–8.PubMedGoogle Scholar
  46. 46.
    Lewis BL, Montgomery H. The senile nail. J Invest Dermatol. 1955;24(1):11–8.PubMedGoogle Scholar
  47. 47.
    de Berker D, Angus B. Proliferative compartments in the normal nail unit. Br J Dermatol. 1996;135(4):555–9.PubMedGoogle Scholar
  48. 48.
    de Berker DA, Andre J, Baran R. Nail biology and nail science. Int J Cosmet Sci. 2007;29(4):241–75.PubMedGoogle Scholar
  49. 49.
    Lovibond JL. Diagnosis of clubbed fingers. Lancet. 1938;1:363.Google Scholar
  50. 50.
    Jarrett A, Spearman RI. The histochemistry of the human nail. Arch Dermatol. 1966;94(5):652–7.PubMedGoogle Scholar
  51. 51.
    Baran R. Nail growth direction revisited. Why do nails grow out instead of up? J Am Acad Dermatol. 1981;4(1):78–84.PubMedGoogle Scholar
  52. 52.
    Kligman AM. Nail growth direction revisited (response). J Am Acad Dermatol. 1981;4:82.Google Scholar
  53. 53.
    Kato N. Vertically growing ectopic nail. J Cutan Pathol. 1992;19(5):445–7.PubMedGoogle Scholar
  54. 54.
    Chaniotakis I, Bonitsis N, Stergiopoulou C, Kiorpelidou D, Bassukas ID. Dizygotic twins with congenital malalignment of the great toenails: reappraisal of the pathogenesis. J Am Acad Dermatol. 2007;57(4):711–5.PubMedGoogle Scholar
  55. 55.
    Lee DY, Park JH, Shin HT, Jang KT, Kwon GY, Shim JS. Onychodermis (specialized nail mesenchyme) containing onychofibroblasts in horizontal sections of the nail unit. Br J Dermatol. 2012;166(5):1127–9.PubMedGoogle Scholar
  56. 56.
    Lee DY, Park JH, Shin HT, Yang JM, Jang KT, Kwon GY, Lee KH, Shim JS. The presence and localization of onychodermis (specialized nail mesenchyme) containing onychofibroblasts in the nail unit: a morphological and immunohistochemical study. Histopathology. 2012b;61(1):123–30.PubMedGoogle Scholar
  57. 57.
    Sellheyer K, Nelson P. The concept of the onychodermis (specialized nail mesenchyme): an embryological assessment and a comparative analysis with the hair follicle. J Cutan Pathol. 2013;40(5):463–71.PubMedGoogle Scholar
  58. 58.
    Pinkus H, Iwasaki T, Mishima Y. Outer root sheath keratinization in anagen and catagen of the mammalian hair follicle. A seventh distinct type of keratinization in the hair follicle: trichilemmal keratinization. J Anat. 1981;133(Pt 1):19–35.PubMedPubMedCentralGoogle Scholar
  59. 59.
    Samman PD. The ventral nail. Arch Dermatol. 1961;84:1030–3.PubMedGoogle Scholar
  60. 60.
    Soon PS, Arnold MA, Tracey DJ. Paraterminal ligaments of the distal phalanx. Acta Anat (Basel). 1991;142(4):339–46.Google Scholar
  61. 61.
    Zook EG. Injuries of the fingernail. In: Green DP, editor. Operative hand surgery, vol. 1. New York: Churchill Livingstone; 1982.Google Scholar
  62. 62.
    Smith DO, Oura C, Kimura C, Toshimori K. Artery anatomy and tortuosity in the distal finger. J Hand Surg Am. 1991;16(2):297–302.PubMedGoogle Scholar
  63. 63.
    Smith DO, Oura C, Kimura C, Toshimori K. The distal venous anatomy of the finger. J Hand Surg Am. 1991;16(2):303–7.PubMedGoogle Scholar
  64. 64.
    Wolfram-Gabel R, Sick H. Vascular networks of the periphery of the fingernail. J Hand Surg Br. 1995;20(4):488–92.PubMedGoogle Scholar
  65. 65.
    Zook EG, Russell RC. Reconstruction of a functional and esthetic nail. Hand Clin. 1990;6(1):59–68.PubMedGoogle Scholar
  66. 66.
    McGinley KJ, Larson EL, Leyden JJ. Composition and density of microflora in the subungual space of the hand. J Clin Microbiol. 1988;26(5):950–3.PubMedPubMedCentralGoogle Scholar
  67. 67.
    Rayan GM, Flournoy DJ. Microbiologic flora of human fingernails. J Hand Surg Am. 1987;12(4):605–7.PubMedGoogle Scholar
  68. 68.
    Andre J, Sass U, Richert B, Theunis A. Nail pathology. Clin Dermatol. 2013;31(5):526–39.PubMedGoogle Scholar
  69. 69.
    Fernandez-Flores A, Saeb-Lima M, Martinez-Nova A. Histopathology of the nail unit. Rom J Morphol Embryol. 2014;55(2):235–56.PubMedGoogle Scholar
  70. 70.
    González-Serva A. Chapter 36: disorders of the nail apparatus. In: Barnhill REIC, Crowson AN, Magro CM, Piepkorn MW, editors. Textbook of dermatopathology. New York: McGraw-Hill Medical; 2010. p. 983.Google Scholar
  71. 71.
    Martin B. Nail histopathology. Actas Dermosifiliogr. 2013;104(7):564–78.PubMedGoogle Scholar
  72. 72.
    Stewart CL, Rubin AI. Update: nail unit dermatopathology. Dermatol Ther. 2012;25(6):551–68.PubMedGoogle Scholar
  73. 73.
    Jerasutus S. Histopathology (of nail diseases). In: D CI, Scher RK, editors. Nails: diagnosis, therapy, surgery. Philadelphia: Elsevier Saunders; 2005. p. 37–71.Google Scholar
  74. 74.
    Scher RK, Daniel CR. Nails: diagnosis, therapy, surgery. Philadelphia: Elsevier Saunders; 2005.Google Scholar
  75. 75.
    Stephen S, Tosti A, Rubin AI. Diagnostic applications of nail clippings. Dermatol Clin. 2015;33(2):289–301.PubMedGoogle Scholar
  76. 76.
    Werner B, Fonseca GP, Seidel G. Microscopic nail clipping findings in patients with psoriasis. Am J Dermatopathol. 2015;37(6):429–39.PubMedGoogle Scholar
  77. 77.
    Braswell MA, Daniel CR 3rd, Brodell RT. Beau lines, onychomadesis, and retronychia: a unifying hypothesis. J Am Acad Dermatol. 2015;73(5):849–55.PubMedGoogle Scholar
  78. 78.
    Tirado-Gonzalez M, Gonzalez-Serva A. The nail plate biopsy may pick up gout crystals and other crystals. Am J Dermatopathol. 2011;33(4):351–3.PubMedGoogle Scholar
  79. 79.
    González-Serva A. Supraungual hyperkeratosis: thickening of the true cuticle as an often unrecognized sign of nail disease (abstract). Am J Dermatopathol. 2013;35(5):e82.Google Scholar
  80. 80.
    González-Serva A. Pigmented sheets in a nail-plate biopsy: mirrors of melanin-producing onychometameres. Am J Dermatopathol. 2007;29(2):204.Google Scholar
  81. 81.
    Braun RP, Baran R, Saurat JH, Thomas L. Surgical pearl: dermoscopy of the free edge of the nail to determine the level of nail plate pigmentation and the location of its probable origin in the proximal or distal nail matrix. J Am Acad Dermatol. 2006;55(3):512–3.PubMedGoogle Scholar
  82. 82.
    Anolik RB, Elenitsas R, Minakawa S, Nguyen J, Rubin AI. Histologic features of nail cosmetics. Am J Dermatopathol. 2012;34(4):412–5.PubMedGoogle Scholar
  83. 83.
    Gupta AK, Daigle D, Carviel JL. The role of biofilms in onychomycosis. J Am Acad Dermatol. 2016;74(6):1241–6.PubMedGoogle Scholar
  84. 84.
    Burkhart CN, Burkhart CG, Gupta AK. Dermatophytoma: recalcitrance to treatment because of existence of fungal biofilm. J Am Acad Dermatol. 2002;47(4):629–31.PubMedGoogle Scholar
  85. 85.
    von Eiff C, Peters G, Heilmann C. Pathogenesis of infections due to coagulase-negative staphylococci. Lancet Infect Dis. 2002;2(11):677–85.Google Scholar
  86. 86.
    Dessinioti C, Katsambas A. Propionibacterium acnes and antimicrobial resistance in acne. Clin Dermatol. 2017;35(2):163–7.PubMedGoogle Scholar
  87. 87.
    Pitts NB, Zero DT, Marsh PD, Ekstrand K, Weintraub JA, Ramos-Gomez F, Tagami J, Twetman S, Tsakos G, Ismail A. Dental caries. Nat Rev Dis Primers. 2017;3:17030.PubMedGoogle Scholar
  88. 88.
    Hernández M, Cuevas MC, González-Serva A. Osmotically swollen cocci in the nail as prototheca-like impostors (abstract). Am J Dermatopathol. 2011;33(4):422.Google Scholar
  89. 89.
    González-Serva A, Paniz-Mondolfi A. Nail erythrasma: rediscovered bacterial disease of ungual keratins (abstract). J Cutan Pathol. 2014;41(2):164.Google Scholar
  90. 90.
    Tirado-González M, González-Serva A. The nail plate biopsy may pick up gout crystals and other crystals (abstract). Am J Dermatopathol. 2010;32(4):406.Google Scholar
  91. 91.
    Perrin C. Tumors of the nail unit. A review. Part I: acquired localized longitudinal melanonychia and erythronychia. Am J Dermatopathol. 2013;35(6):621–36.PubMedGoogle Scholar
  92. 92.
    Perrin C. Tumors of the nail unit. A review. Part II: acquired localized longitudinal pachyonychia and masked nail tumors. Am J Dermatopathol. 2013;35(7):693–709. quiz 710–692PubMedGoogle Scholar
  93. 93.
    Richert B, Lecerf P, Caucanas M, Andre J. Nail tumors. Clin Dermatol. 2013;31(5):602–17.PubMedGoogle Scholar
  94. 94.
    Schwager ZA, Mannava KA, Mannava S, Telang GH, Robinson-Bostom L, Jellinek NJ. Superficial acral fibromyxoma and other slow-growing tumors in acral areas. Cutis. 2015;95(2):E15–9.PubMedGoogle Scholar
  95. 95.
    Eun YS, Kim MR, Cho BK, Yoo G, Park HJ. Subungual soft tissue chondroma with nail deformity in a child. Pediatr Dermatol. 2015;32(1):132–4.PubMedGoogle Scholar

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© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  • Aldo González-Serva
    • 1
  1. 1.Quantum PathologyWalthamUSA

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