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Dermatology Research and Practice
Volume 2012, Article ID 925023, 3 pages
Review Article

Nail Isthmus: A Distinct Region of the Nail Apparatus

1Department of Dermatology, Kinki University Faculty of Medicine, Osaka-Sayama 589-8511, Japan
2Department of Dermatology, Acne Clinical and Research Center, Meiwa Hospital, Nishinomiya 663-8186, Japan

Received 31 July 2011; Revised 12 September 2011; Accepted 13 November 2011

Academic Editor: Eckart Haneke

Copyright © 2012 Naoki Oiso et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The nail unit is constructed by distinctly regulated components. The nail isthmus is a lately proposed region as a transitional zone between the most distal part of the nail bed and the hyponychium. It is difficult to recognize the nail isthmus in the normal nail, but it is easy to identify the region in nail disorders such as pterygium inversum unguis and ectopic nail. We describe structure and putative function of the nail isthmus via histopathologic features of pterygium inversum unguis and ectopic nail.