Stephen J. Schueler, M.D.

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Blood Under the Nail Anatomy

To better understand subungual hematoma, it helps to understand the anatomy of the fingernail.

Fingernail Anatomy

  • Nail plate:
    • This is another name for the fingernail
  • Matrix:
    • This is the portion of the nail that produces the nail plate. Cells in the matrix eventually form the nail plate
  • Lunula:
    • The white "half moon shaped" area at the base of the nail. The matrix extends down to the edge of the lunula
  • Hyponychium:
    • The hyponychium is the junction of the nail bed and the fingertip skin, beneath the distal free margin of the nail plate
  • Nail bed:
    • The nail bed extends from the lunula to the hyponychium. As additional cells are produced by the matrix, the nail plate progresses (grows) distally on the surface of the nail bed. The nail bed acts as a guiding surface for the advancing nail plate.
  • Eponychium:
    • The thin skin adherent to the nail at its base
  • Perionychium or nail groove:
    • The lateral skin fold; the nail grows distally because it is guided by this fold of skin. Infection or injury to the area can result in a deformed or ingrown nail.

Last Updated: Jan 5, 2011 References
Authors: Stephen J. Schueler, MD; John H. Beckett, MD; D. Scott Gettings, MD
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PubMed Blood Under the Nail References
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  2. Chan J, Spencer J. Adaptation to hand injury: an evolving experience. Am J Occup Ther. 2004 Mar-Apr;58(2):128-39. [15068148]
  3. Gustafsson M, Ahlstrom G. Problems experienced during the first year of an acute traumatic hand injury - a prospective study. J Clin Nurs. 2004 Nov;13(8):986-95. [15533105]
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