title: Manual fixation versus locking during upper cervical segmental mobilization. Part 2: an in vitro three-dimensional arthrokinematic analysis of manual axial rotation and lateral bending mobilization of the atlanto-axial joint.
abstract: BACKGROUND
  Three-dimensional kinematic aspects of coupled motion during manual cervical mobilization have not previously been studied. Using an in vitro 3D-motion analysis method, the kinematic effects of two different segmental techniques for axial rotation and lateral bending mobilization of the upper cervical spine were investigated as a second part of the study (in part one, kinematic effects of flexion-extension mobilization have been investigated).
  
  
  METHODS
  Axial rotation and lateral bending mobilization of the atlanto-occipital and atlanto-axial segments were analysed in vitro using an electromagnetic tracking device. Local reference frames were defined based on bony reference points that were registered using a 3D-digitizing stylus. Five embalmed and one fresh specimen were analysed. Segmental motion was registered simultaneously in the atlanto-occipital and the atlanto-axial joints during manual mobilization through the full range of axial rotation and lateral bending mobility. The 3D-kinematic aspects during regional mobilization were compared with those during segmental mobilization with manual fixation and during segmental mobilization using a locking technique.
  
  
  RESULTS
  During both segmental axial rotation techniques of the atlanto-axial joint, a significant reduction of the coupled lateral bending and flexion-extension motion was observed. The locking technique also induced an increase in the main axial rotation component. During lateral bending mobilization of the atlanto-axial joint, the manual fixation technique reduced the effect on the coupled flexion-extension component significantly.
  
  
  CONCLUSIONS
  These results suggest that for manual segmental axial rotation and lateral bending mobilization of the upper cervical spine segmental manual fixation or locking may be preferred in different situations depending on the desired effects. This study brings additional information to the data provided by part 1 of this study on the 3D-arthrokinematic effects of flexion-extension mobilization.
authors.affiliation: Vrije Universiteit Brussel, Department of Experimental Anatomy (EXAN), Laarbeeklaan 103, B1090 Brussels, Belgium. ecattrys@vub.ac.be
authors.forename: E
authors.initials: E
authors.lastname: Cattrysse
authors.forename: J P
authors.initials: JP
authors.lastname: Baeyens
authors.forename: J P
authors.initials: JP
authors.lastname: Clarys
authors.forename: P
authors.initials: P
authors.lastname: Van Roy
mesh_terms: D001268:Atlanto-Axial Joint / Q000502:physiology*; D001696:Biomechanical Phenomena; D002102:Cadaver; D002574:Cervical Vertebrae / Q000033:anatomy & histology; D055590:Electromagnetic Phenomena; D006801:Humans; D008875:Middle Aged; D026201:Musculoskeletal Manipulations / Q000379:methods*; D016059:Range of Motion, Articular; D012399:Rotation