title: Biomechanics of the cricoarytenoid joint: three-dimensional imaging and vector analysis.
abstract: OBJECTIVE
  Laryngeal framework surgery requires a good understanding of the biomechanics of the cricoarytenoid (CA) joint, the precise function of which is still only poorly understood. The aim of the study was (1) to show that, by superimposing two or more three-dimensional (3D) images, we can visualize the exact position of the arytenoid cartilages within the larynx at different phases of their movement; and (2) to demonstrate that it is possible to analyze the arytenoid cartilage movements mathematically with the help of vector analysis.
  
  
  METHODS
  In vitro cadaver study.
  
  
  METHODS
  Twenty fresh and intact cadaver larynges were scanned by high-resolution computerized tomography with the arytenoid cartilages in "respiratory" position and in "phonatory" position. The two positions were superimposed and rendered in 3D with MIMICS (Materialise Interactive Medical Image Control System, Leuven, Belgium). The spatial trajectory of the arytenoid cartilage movements was calculated with vector analysis.
  
  
  RESULTS
  The movement from the "respiratory" to the "phonatory" position has three components: (1) an inward rocking action around the longitudinal CA joint; (2) a forward sliding movement along the longitudinal axis of the CA joint; and (3) an inward rotation around a virtual axis that runs perpendicular to the CA joint axis.
  
  
  CONCLUSIONS
  Superimposing 3D images of the larynx with the help of the software package MIMICS allows us to visualize and to analyze mathematically the trajectory of the arytenoid cartilage. The arytenoid cartilages rock inward, slide forward, and rotate inward when they move from the "respiratory" to the "phonatory" position.
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Basel, Basel, Switzerland. cstorck@uhbs.ch
authors.forename: Claudio
authors.initials: C
authors.lastname: Storck
authors.forename: Philipp
authors.initials: P
authors.lastname: Juergens
authors.forename: Claude
authors.initials: C
authors.lastname: Fischer
authors.forename: Markus
authors.initials: M
authors.lastname: Wolfensberger
authors.forename: Flurin
authors.initials: F
authors.lastname: Honegger
authors.forename: Erich
authors.initials: E
authors.lastname: Sorantin
authors.forename: Gerhard
authors.initials: G
authors.lastname: Friedrich
authors.forename: Markus
authors.initials: M
authors.lastname: Gugatschka
mesh_terms: D000368:Aged; D001193:Arytenoid Cartilage / Q000033:anatomy & histology / Q000502:physiology*; D001696:Biomechanical Phenomena; D003413:Cricoid Cartilage / Q000033:anatomy & histology / Q000502:physiology*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D012399:Rotation