Comparison of Changes in the Transversus Abdominis and Neighboring Fascia in Subjects With and Without a History of Low Back Pain Using Ultrasound Imaging

[Purpose] This study attempted to clarify the relationship between low back pain and changes in the abdominal and thoracolumbar fascias that are caused by contraction of the transversus abdominis. [Subjects] The subjects were 51 men with a mean age of 22.9 ± 4.0 years. [Methods] A medical history was obtained from all subjects through interviews and each person was assigned to one of 3 groups in relation to experience of low back pain. Subjects' abdominal girth at the umbilical level was measured from the anterior, antero-lateral and posterior parts and recorded using an ultrasound US diagnostic device during rest and contraction of the transversus abdominis. [Results] Contraction of the transversus abdominis was confirmed by observing the US image, while the subjects were urged to make a conscious effort to contract the muscle. In the group of those who had been treated for low back pain, the distance covered by the movement of the abdominal fascia and that of the tip of the transversus abdominis (musculotendinous junction) was reduced in spite of contraction occurring at a uniform level. [Conclusion] The results indicate that there is a correlation between the mobility of the abdominal and thoracolumbar fascias and a history of low back pain. This suggests that analysis of the movement of each fascia, measuring the distance covered by the movements of the abdominal fascia and the tip of transversus abdominis(TA) instead of measuring the muscle thickness of TA alone, would be effective for providing an understanding of the etiology of low back pain and the segmental stability of the spine.