title: Relationship between low back pain and lumbar multifidus size at different postures.
abstract: METHODS
  A prospective study of multifidus images. OBJECTIVE.: To compare the change of the cross-sectional area (CSA) of multifidus in subjects with and without chronic low back pain (LBP) at different postures.
  
  
  BACKGROUND
  Ultrasound imaging was shown to be useful in assessing acute LBP patients at rest only.
  
  
  METHODS
  Thirty-five male adults participated, including 19 normal and 16 chronic LBP patients. The CSAs of multifidus were assessed on ultrasound images acquired on both sides of the L4 and L5 levels with the subjects in prone lying, upright standing, and 25 degrees and 45 degrees forward stooping.
  
  
  RESULTS
  In the control group, the CSA of multifidus increased from prone lying to upright standing and then gradually decreased from 25 degrees to 45 degrees forward stooping. However, a reverse pattern of the CSA changes was identified in patients with chronic LBP.
  
  
  CONCLUSIONS
  Multifidus contracts maximally at upright standing in the normal group, while maximum contraction of the muscle occurs at 25 degrees forward stooping in the patient group. The role of multifidus may be altered in the stabilization of the lumbar spine of chronic LBP patients. Assessment of the change in muscle size reacting to different postures is found to be helpful.
authors.affiliation: Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hunghom, Kowloon, Hong Kong.
authors.forename: Sai-wing
authors.initials: SW
authors.lastname: Lee
authors.forename: Clement Kin-ming
authors.initials: CK
authors.lastname: Chan
authors.forename: Tat-sang
authors.initials: TS
authors.lastname: Lam
authors.forename: Ching
authors.initials: C
authors.lastname: Lam
authors.forename: Nga-chi
authors.initials: NC
authors.lastname: Lau
authors.forename: Rufina Wing-lum
authors.initials: RW
authors.lastname: Lau
authors.forename: Suk-tak
authors.initials: ST
authors.lastname: Chan
mesh_terms: D000328:Adult; D019412:Anatomy, Cross-Sectional; D006801:Humans; D017116:Low Back Pain / Q000209:etiology* / Q000503:physiopathology; D008159:Lumbar Vertebrae / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging*; D011187:Posture; D011446:Prospective Studies; D014463:Ultrasonography