title: Paraspinal muscles and intervertebral dysfunction: part one.
abstract: BACKGROUND
  One of the diagnostic characteristics of the manipulable spinal lesion--a musculoskeletal disturbance detected by manual palpation and corrected with manipulation--is said to be altered segmental tissue texture. Various manual therapy authors have speculated on the possible nature of this tissue change, with some authors hypothesizing that it represents deep segmental muscle overactivity.
  
  
  OBJECTIVE
  To review the literature relating to the detection and nature of altered paraspinal tissue texture, proposed explanations for altered tissue texture, evidence for the plausibility of paraspinal muscle spasm, and evidence of muscle dysfunction associated with low back pain (LBP).
  
  
  METHODS
  MEDLINE and CINAHL databases were searched using various combinations of the keywords paraspinal, muscle, palpation, EMG, spine, low back pain, pain, myofascial, hardness, manipulation, reliability, and somatic dysfunction, along with searching the bibliographies of selected articles and textbooks.
  
  
  METHODS
  All relevant data were used.
  
  
  RESULTS
  Little direct evidence exists for the nature of abnormal paraspinal tissue texture detected by palpation. Palpation for tenderness is more reliable than palpation for tissue texture change. Indirect evidence from animal studies and experimental muscle inflammation support the plausibility of protective paraspinal muscle contraction. Increased paraspinal electromyographic (EMG) activity observed in subjects with LBP appears to be a result of voluntary and nonvoluntary changes in motor control, modified by psychophysiological responses to perceived stress rather than a simple protective reflex.
  
  
  CONCLUSIONS
  Although little direct evidence exists of the nature of clinically detected paraspinal tissue texture change, the concept of reactive muscle contraction appears plausible. Increased paraspinal EMG activity associated with LBP does not appear to be mediated by a simple protective reflex.
authors.affiliation: School of Health Science, Victoria University, City Campus, PO Box 14428 MCMC, Melbourne 8001, Australia. gary.fryer@vu.edu.au
authors.forename: Gary
authors.initials: G
authors.lastname: Fryer
authors.forename: Tony
authors.initials: T
authors.lastname: Morris
authors.forename: Peter
authors.initials: P
authors.lastname: Gibbons
mesh_terms: D004576:Electromyography; D006801:Humans; D007403:Intervertebral Disc / Q000503:physiopathology*; D007405:Intervertebral Disc Displacement / Q000150:complications / Q000503:physiopathology*; D017116:Low Back Pain / Q000209:etiology / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000503:physiopathology*; D012018:Reflex; D012585:Sciatica / Q000209:etiology / Q000503:physiopathology; D016474:Weight-Bearing