title: Visibility and variability of pleural fissures on normal digital chest radiographs of 1,000 healthy adults.
abstract: OBJECTIVE
  To investigate the visibility and variability of pleural fissures on digital chest radiographs.
  
  
  METHODS
  Posteroanterior digital chest radiographs of 566 males and 434 females were retrospectively reviewed for the frequencies and/or appearances of various pleural fissures.
  
  
  RESULTS
  The right only, left only and bilateral minor fissures were visible in 722 (72.2 %), 1 (0.1 %) and 7 (0.7 %) subjects, respectively. The right minor fissures were visible as more than one line in 219 (30.0 %) subjects, i.e., 2, 3 and 4 lines in 214 (29.3 %), 4 (0.5 %) and 1 (0.1 %), respectively. The 955 visible right minor fissures exhibited variable length (<1/3 of right hemithorax, 17.8 %; 1/3-2/3, 60.1 %; >2/3, 22.1 %), alignment (medial higher 40.9 %; lateral higher 54.2 %; horizontal 4.8 %) and contour (convex upward 68.6 %; convex downward 2.7 %; flat 24.9 %; sigmoid 3.8 %). Superolateral major fissures were visualized in 14.8 % (right only 3.0 %; left only 9.0 %; bilateral 2.8 %), superomedial major fissures in 0.3 % (right 0.1 %; left 0.2 %), vertical fissures in 0.5 % (right 0.2 %; left 0.3 %), inferior accessory fissures in 5.4 % (right 4.8 %; left 0.6 %), right superior accessory fissures in 1.2 % and azygos fissures in 0.2 %.
  
  
  CONCLUSIONS
  The right minor fissure was most frequently visible and exhibited variable appearances. Other pleural fissures were occasionally seen.
authors.affiliation: Division of Diagnostic Radiology, Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, 270, Rama VI Road, Ratchathewi, Bangkok, 10400, Thailand, ratrspoom@yahoo.com.
authors.forename: Thitiporn
authors.initials: T
authors.lastname: Suwatanapongched
authors.forename: Chinnarat
authors.initials: C
authors.lastname: Bua-Ngam
authors.forename: Warawut
authors.initials: W
authors.lastname: Sukkasem
authors.forename: Hathaichanok
authors.initials: H
authors.lastname: Choochuay
authors.forename: Parinda
authors.initials: P
authors.lastname: Charee
authors.forename: Suvipaporn
authors.initials: S
authors.lastname: Siripornpitak
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010994:Pleura / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D013902:Radiography, Thoracic; D012189:Retrospective Studies