title: Ultrasonographic analysis of dorsal neck muscles thickness changes induced by isometric contraction of shoulder muscles: A comparison between patients with chronic neck pain and healthy controls.
abstract: BACKGROUND
  Altered pattern of muscle activity is commonly seen with chronic neck pain (CNP). However, limited investigations have been done on dorsal neck muscles' activity pattern while performing upper limb tasks in patients with CNP.
  
  
  OBJECTIVE
  To investigate dorsal neck muscles' thickness changes during isometric contraction of shoulder muscles.
  
  
  METHODS
  Case-control study.
  
  
  METHODS
  This study investigated dorsal neck muscles' thickness changes during isometric contraction of shoulder muscles in 20 healthy participants (mean age 27 ± 4.37) and 17 patients with CNP (mean age 29 ± 5.50). Effects of isometric force of shoulder muscles on dorsal neck muscles' thickness changes were also evaluated.
  
  
  RESULTS
  Significant muscle × group interaction was observed for the dorsal neck muscles thickness changes (p = 0.008) indicating different pattern of muscle activity in terms of changes in muscle thickness of two groups. Significant main effects of direction was observed (P = 0.003), with the abduction had the greatest impact on changing the dorsal neck muscles thickness.
  
  
  CONCLUSIONS
  patients with CNP showed altered pattern of muscle thickness changes in comparison to healthy participants. Isometric abduction of shoulder muscles induced the greatest changes of dorsal neck muscles thickness among other force directions.
authors.affiliation: Department of Physiotherapy, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran.
authors.forename: Noureddin
authors.initials: N
authors.lastname: Karimi
authors.affiliation: Faculty of Rehabilitation, Physiotherapy Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran; Department of Physiotherapy, Faculty of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Asghar
authors.initials: A
authors.lastname: Rezasoltani
authors.affiliation: Department of Physiotherapy, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. Electronic address: lrahnama@gmail.com.
authors.forename: Leila
authors.initials: L
authors.lastname: Rahnama
authors.affiliation: Department of Radiology, Medical Imaging Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Farhang
authors.initials: F
authors.lastname: Noori-Kochi
authors.affiliation: Department of Physiotherapy, School of Primary Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Frankston, Australia.
authors.forename: Shapour
authors.initials: S
authors.lastname: Jaberzadeh
mesh_terms: D000328:Adult; D064131:Back Muscles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D016022:Case-Control Studies; D059350:Chronic Pain / Q000503:physiopathology*; D004576:Electromyography; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D009334:Neck Muscles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D019547:Neck Pain / Q000503:physiopathology*; D014463:Ultrasonography; D055815:Young Adult
keywords: Isometric contraction; Neck muscles; Neck pain; Shoulder; Ultrasonography