title: Secular trend in the opening of the sacral canal: an Australian study.
abstract: METHODS
  Computer tomography scans were used to asses the opening of the sacral canal.
  
  
  OBJECTIVE
  We investigated the prevalence of sacral spina bifida occulta in 2 population groups: born 1940 to 1950 and 1980 to 1990.
  
  
  BACKGROUND
  Comparison of the prevalence of spina bifida occulta in the first-century Pompeii with that in 20th century European and Mediterranean populations indicates that the degree of the closure of vertebral arches in the sacrum has undergone changes and the prevalence of spina bifida occulta is increasing.
  
  
  METHODS
  Transverse computer tomograph scans and multiplanar reconstruction images of sacra of 100 males and 100 females born 1940 to 1950 and 100 males and 100 females born 1980 to 1990 were used after ethics committee approval.
  
  
  RESULTS
  The individuals born later have significantly more open sacral arches when compared with those born 40 years earlier, especially in the midsacral region. Also, males have open sacral arches in the rostral segments of the sacrum more than females.
  
  
  CONCLUSIONS
  This study demonstrates a secular trend in the opening of the sacral canal in both sexes that occurred within 2 generations. Also, the increased prevalence of open sacral canal in males suggests a different response between sexes to the forces of evolution.
authors.affiliation: Department of Orthopaedics and Trauma, University of Adelaide and Royal Adelaide Hospital, University of Adelaide, Adelaide, South Australia, Australia. bogdansolomon@mac.com
authors.forename: Lucian Bogdan
authors.initials: LB
authors.lastname: Solomon
authors.forename: Frank Jakobus
authors.initials: FJ
authors.lastname: Rühli
authors.forename: Yu Chao
authors.initials: YC
authors.lastname: Lee
authors.forename: Maciej
authors.initials: M
authors.lastname: Henneberg
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000886:Anthropometry; D001106:Archaeology; D001315:Australia; D044127:Epigenesis, Genetic / Q000235:genetics; D005260:Female; D014644:Genetic Variation; D049673:History, 20th Century; D049690:History, Ancient; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D019655:Quantitative Trait, Heritable; D012447:Sacrum / Q000002:abnormalities* / Q000000981:diagnostic imaging*; D012727:Sex Characteristics; D016136:Spina Bifida Occulta / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000266:history; D014057:Tomography, X-Ray Computed / Q000379:methods*; D055815:Young Adult