title: What does the geometry of an arc reveal about methods of assessing spinal radiographs in scoliosis?
abstract: BACKGROUND
  The shapes of an arc and scoliosis are the same. Therefore, the geometry of an arc can reveal the relationship between the angles within and around a scoliotic spine.
  
  
  OBJECTIVE
  To look for angles which are functions of the geometry of an arc and can also be used for assessment of curve progression in scoliosis.
  
  
  METHODS
  Review of the geometry of an arc and that of scoliosis.
  
  
  METHODS
  English literature on scoliosis (from 1930 to date), searched manually, via Internet and from colleagues, was reviewed.
  
  
  RESULTS
  Methods of curve measurement in use presently are functions of the geometry of scoliosis. Three additional methods are proposed for assessment of curve progression in scoliosis. These methods are geometrically related with the previously known ones.
  
  
  CONCLUSIONS
  All methods of assessment of curve progression in scoliosis are fundamentally the same and interchangeable. There is no reason for preference of one method over another method of curve measurement.
authors.affiliation: Department of Surgery, Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria. agabamusa@yahoo.com
authors.forename: Abdullahi Agaba-Idu
authors.initials: AA
authors.lastname: Musa
mesh_terms: D006801:Humans; D011859:Radiography / Q000379:methods*; D012600:Scoliosis / Q000000981:diagnostic imaging*