Investigation of Structure and Action of Spinal Muscles Using USI, MRI, and EMG Methods in Individuals with Sway-Back Postur

Sway-Back Posture (SBP) is one of the most common spinal malalignments, especially among young women. However, among different researchers, still there is not an agreement concerning the structural and muscular changes in lumbar and pelvic regions. The aim of the present study was to survey the structural changes and action of spinal muscles in individuals with SBP, using accurate methods like USI, MRI, and EMG.
During our search in Google Scholar, Pubmed, and Embase, at first 102 articles published between 2002 and 2016 were found. After matching with inclusion and exclusion criteria, 97 articles were deleted and full texts of 5 articles were reviewed. We used the articles which were more concerned with the muscle changes in SBP using accurate techniques like USI, MRI, and EMG.
Electromyography studies indicated that internal oblique, multifidus, and erector spine muscles were less active and rectus abdominus muscle was more active than other spinal postural muscles in SBP. Ultrasonography studies showed that the thickness of transvers abdominus was smaller in SBP than in others. Using MRI, it was revealed that fat was infiltrated in multifidus and erector spine muscles in SBP more than that in the other spinal postural muscles.
Findings of the studies reviewed showed that the structure of deep lumbar and abdomen muscles were changed accordingly which may lead to instability in lumbo-pelvic areas in individuals with SBP. In the present review, we found that all three methods of muscular assessment provided key knowledge concerning the structure and the action of spinal muscle in individuals with SBP.