title: Primary and coupled cervical movements: the effect of age, gender, and body mass index. A 3-dimensional movement analysis of a population without symptoms of neck disorders.
abstract: METHODS
  Exploratory experimental design.
  
  
  OBJECTIVE
  To examine primary and coupled cervical movements, and to study the effects of age, gender, and body mass index in a "neck-healthy" population. These data could serve as a basis for future interventions and to assess normal variations.
  
  
  BACKGROUND
  Cervical movements are biomechanically and neurophysiologically complex. Neck disorders and trauma most often influence cervical movements. With 3-dimensional recordings, it is possible to make precise, noninvasive evaluations of how the head moves on the stable trunk, and to analyze primary and coupled movements.
  
  
  METHODS
  A total of 120 subjects (60 men and 60 women, ages 20-79), were tested with Zebris (Zebris Medizintechnik GmbH, Isny, Germany), a 3-dimensional movement analyzer.
  
  
  RESULTS
  Age influences the majority of primary and coupled movements. With increasing age, primary movement size decreases in all cardinal planes. Age most strongly affects the coupled movements of primary rotation and lateral flexion. Gender and body mass index have only slight influences.
  
  
  CONCLUSIONS
  Coupled movements are a natural part of cervical motion together with primary movements and follow specific patterns in subjects with no symptoms of neck disorders. Our study shows that cervical motion alters throughout life according to specific patterns but with individual variations.
authors.affiliation: Department of Rehabilitation, Lund University Hospital, Sweden. eva-maj.malmstrom@skane.se
authors.forename: Eva-Maj
authors.initials: EM
authors.lastname: Malmström
authors.forename: Mikael
authors.initials: M
authors.lastname: Karlberg
authors.forename: Per Anders
authors.initials: PA
authors.lastname: Fransson
authors.forename: Agneta
authors.initials: A
authors.lastname: Melander
authors.forename: Måns
authors.initials: M
authors.lastname: Magnusson
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D002574:Cervical Vertebrae / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D009334:Neck Muscles / Q000502:physiology*; D012399:Rotation; D012737:Sex Factors