title: 3-D analysis of dislocation in zygoma fractures.
abstract: OBJECTIVE
  When fractured, zygomas rotate and dislocate. The present study quantitatively elucidates the pattern of the rotation.
  
  
  METHODS
  50 patients with tri-pod-type zygoma fractures were involved in this study. After defining a 3-dimensional coordinate system--consisting of the M-L axis (the axis directed from the medial to lateral side of the skull), I-S axis (directed from the inferior to superior side), and P-A axis (directed from the posterior to anterior side), the degree with which the fractured zygomas rotated around each of these axes was measured using 3-dimensional graphic software. Thereafter, the tendency of the rotation was compared between the three rotational axes.
  
  
  RESULTS
  Rotation around the I-S axis was the most frequent with a 96% incidence, followed by a substantial margin by rotation around the M-L axis with a 26% incidence; rotation around the P-A axis was rare, with an incidence of 10%. Furthermore, the degree of P-A axis rotation was minor compared to I-S and M-L axis rotations.
  
  
  CONCLUSIONS
  The main factor of zygoma dislocation in zygoma fracture is rotation around the I-S axis. This finding is helpful for effective performance to reposition fractured zygomas.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Keio University, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Toriumi
authors.affiliation: Department of Plastic and Reconstructive Surgery, Keio University, Tokyo, Japan. Electronic address: nagasao@z6.keio.jp.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Nagasao
authors.affiliation: Design Faculty, Tokyo University of Technology, Tokyo, Japan.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Itamiya
authors.affiliation: Department of Plastic and Reconstructive Surgery, Keio University, Tokyo, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Shimizu
authors.affiliation: Department of Pediatrics, Tokyo University, Tokyo, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yasudo
authors.affiliation: Department of Plastic and Reconstructive Surgery, Keio University, Tokyo, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Sakamoto
authors.affiliation: Department of Plastic and Reconstructive Surgery, Keio University, Tokyo, Japan.
authors.forename: Hisao
authors.initials: H
authors.lastname: Ogata
authors.affiliation: Department of Plastic and Reconstructive Surgery, Keio University, Tokyo, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Kishi
mesh_terms: D000058:Accidental Falls; D000063:Accidents, Traffic; D000328:Adult; D001265:Athletic Injuries / Q000175:diagnosis; D003198:Computer Simulation; D017076:Computer-Aided Design; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D004204:Joint Dislocations / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D012399:Rotation; D014057:Tomography, X-Ray Computed / Q000379:methods; D014584:User-Computer Interface; D014754:Violence; D015051:Zygomatic Fractures / Q000175:diagnosis*
keywords: Analysis; Diagnosis; Evaluation; Fracture; Reposition; Zygoma