title: CT-based preoperative analysis of scapula morphology and glenohumeral joint geometry.
abstract: OBJECTIVE
  To investigate the geometry of the glenohumeral joint using three-dimensional (3D) models; define landmarks, planes, angles and regions of interest; and analyze the exact morphology of the scapula.
  
  
  METHODS
  We reconstructed 3D scapula models based on computed tomography (CT) data sets of 12 healthy controls. Three-dimensional models were reconstructed using the 3D Slicer2 (Surgical Planning Lab, Boston, MA), which provides interactive measurement. The 3D model and measuring tools can be freely shifted and rotated in all planes.
  
  
  RESULTS
  The average length of the scapulas was 209.58 +/- 26.72 mm (left) and 223.68 +/- 47.74 mm (right); width was 124.03 +/- 13.28 mm (left) and 141.44 +/- 27.78 mm (right); and volume was 121.38 +/- 12.02 ml (left) and 130.24 +/- 20.86 ml (right). The glenoid dimensions were 34.34 +/- 5.62 mm (left) and 36.44 +/- 7.36 mm (right) (anteroposterior); and 49.16 +/- 7.68 mm (left), 51.46 +/- 10.07 mm (right) (superoinferior). For all average values, scapulas from male controls were significantly larger than those from females, and right sides were larger than left sides (p < 0.05). The glenoid version was nearly the same for male/female and left/right (left = 9.02 +/- 3.89 degrees retroversion; right = 8.26 +/- 3.72 degrees retroversion) (p > or = 0.05).
  
  
  CONCLUSIONS
  The 3D measurement of scapula morphology compared with geometry of the glenohumeral joint leads to a more precise planning of shoulder surgery. As new shoulder prostheses are intended to reconstruct the normal anatomy as closely as possible, such exact 3D measurements may be used for optimization.
authors.affiliation: Surgical Planning Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA. welsch@bwh.harvard.edu
authors.forename: Goetz
authors.initials: G
authors.lastname: Welsch
authors.forename: Tallal Charles
authors.initials: TC
authors.lastname: Mamisch
authors.forename: Ron
authors.initials: R
authors.lastname: Kikinis
authors.forename: Rainer
authors.initials: R
authors.lastname: Schmidt
authors.forename: Philipp
authors.initials: P
authors.lastname: Lang
authors.forename: Raimund
authors.initials: R
authors.lastname: Forst
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Fitz
mesh_terms: D003198:Computer Simulation; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011300:Preoperative Care; D012540:Scapula / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D012727:Sex Characteristics; D012785:Shoulder Joint / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D014057:Tomography, X-Ray Computed