title: Anomalies at the thoracic outlet are frequent in the general population.
abstract: BACKGROUND
  Abnormal anatomy at the thoracic outlet is frequent in patients operated on for thoracic outlet syndrome (TOS). The present study was designed to find out the rate of thoracic outlet anomalies in the general population.
  
  
  METHODS
  Fifty cadavers representing a general population were subjected to a total of 98 meticulously performed cervical dissections to ascertain the frequency of congenital anomalies in the thoracocervicoaxillary region.
  
  
  RESULTS
  During the 98 cervical dissections, 62 instances of abnormal anatomy of the thoracic outlet were found, and fully normal anatomy was found in 36 cases. Of the total 69 abnormalies, 66 could be classified according to Roos: 37 were type 3 abnormalities, 15 were type 5, 9 were type 11, and there was 1 each of type 4, type 6, type 7, type 9, and type 10 abnormalities. The remaining 3 abnormalities did not fit into Roos' classification. Only 10% (5/50) of the cadavers had a bilaterally normal anatomy.
  
  
  CONCLUSIONS
  The results demonstrate that abnormal structures, such as congenital bands in the thoracic outlet, are more common in the general population than had previously been described. We suggest that fibrous bands confer a predisposition for TOS following a certain degree of stress or injury.
authors.affiliation: Department of Surgery, University of Oulu, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Juvonen
authors.forename: J
authors.initials: J
authors.lastname: Satta
authors.forename: P
authors.initials: P
authors.lastname: Laitala
authors.forename: K
authors.initials: K
authors.lastname: Luukkonen
authors.forename: J
authors.initials: J
authors.lastname: Nissinen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001917:Brachial Plexus / Q000002:abnormalities; D002102:Cadaver; D000013:Congenital Abnormalities / Q000145:classification / Q000453:epidemiology; D005260:Female; D005387:Finland; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D013348:Subclavian Artery / Q000002:abnormalities; D013901:Thoracic Outlet Syndrome / Q000453:epidemiology*; D013909:Thorax / Q000002:abnormalities*