title: Fingernail Configuration.
abstract: BACKGROUND
  A number of conditions can alter a person's fingernail configuration. The ratio between fingernail width and length (W/L) is an important aesthetic criterion, and some underlying diseases can alter the size of the fingernail. Fingernail curvature can be altered by systemic disorders or disorders of the fingernail itself. Although the shape and curvature of the fingernail can provide diagnostic clues for various diseases, few studies have precisely characterized normal fingernail configuration.
  
  
  METHODS
  We measured the W/L ratio of the fingernail, transverse fingernail curvature, hand length, hand breadth, and distal interphalangeal joint width in 300 volunteers with healthy fingernails. We also investigated whether age, sex, height, and handedness influenced the fingernail W/L ratio and transverse fingernail curvature.
  
  
  RESULTS
  In women, fingernail W/L ratios were similar across all five fingers, and were lower than those in men. The highest value of transverse fingernail curvature was found in the thumb, followed by the index, middle, ring, and little fingers. Handedness and aging influenced transverse fingernail curvature, but not the fingernail W/L ratio. Fingernails were flatter on the dominant hand than on the non-dominant hand. The radius of transverse fingernail curvature increased with age, indicating that fingernails tended to flatten with age.
  
  
  CONCLUSIONS
  Our quantitative data on fingernail configuration can be used as a reference range for diagnosing various diseases and deformities of the fingernail, and for performing reconstructive or aesthetic fingernail surgery.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Jin Woo
authors.initials: JW
authors.lastname: Jung
authors.affiliation: Department of Plastic and Reconstructive Surgery, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Kwang Seog
authors.initials: KS
authors.lastname: Kim
authors.affiliation: Department of Preventive Medicine, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Shin
authors.affiliation: Department of Plastic and Reconstructive Surgery, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Yu Jin
authors.initials: YJ
authors.lastname: Kwon
authors.affiliation: Department of Plastic and Reconstructive Surgery, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Jae Ha
authors.initials: JH
authors.lastname: Hwang
authors.affiliation: Department of Plastic and Reconstructive Surgery, Chonnam National University Medical School, Gwangju, Korea.
authors.forename: Sam Yong
authors.initials: SY
authors.lastname: Lee
keywords: Anthropometry; Fingers; Nail diseases; Nails; Statistics