Relations of Bilateral Symmetry in the Cross-sectional Area of the Quadratus Lumborum Muscles to Posture in the Frontal Plane and Respiratory Function in Forced Breathing

Abstract

The purpose of this study was to investigate the relations of bilateral symmetry in the cross-sectional area of quadratus lumborum muscles with frontal posture and respiratory function. [Subjects and Methods] The subjects were 20 healthy males. Measurement items comprised the cross-sectional area of the quadratus lumborum muscles, frontal posture, thoracic extension rate, respiratory muscle strength, and pulmonary function. [Results] Bilateral asymmetry was observed in the cross-sectional area of quadratus lumborum muscles; the mass of the right quadratus lumborum muscle was larger than that of the left quadratus lumborum muscle. Significant positive correlations were found between bilateral symmetry of the cross-sectional area of the quadratus lumborum muscles and frontal posture, thoracic extension rate, and expiratory muscle strength; and there was a significant negative correlation with the pulmonary function index of residual volume. [Conclusion] The present study revealed relationships between bilateral symmetry in the cross-sectional area of the quadratus lumborum muscles and frontal posture and respiratory function.

Analysis of the asymmetry of thoracic shape at rest: relationship with lateral thoracic deviation

“…The volume of the thorax in each area was calculated as the ratio of left to right (right side data/left side data). The lateral deviation of the thorax was calculated by referring to the method of Homma et al 12 ) ( Fig. 3

Fig.

…”

Relationship between the thoracic asymmetry in standing position and the asymmetry of ankle moment in the frontal plane during gait

“…Based on a significant correlation between the asymmetry of the thoracic shape and respiratory function, Hirayama et al 1 ) suggested that the greater the asymmetry of the thoracic shape, the lower the respiratory function. Homma et al 2 ) and Sano et al. 3 ) also found a significant correlation between the TLD and the asymmetry in the cross-sectional area of the quadratus lumborum and the psoas major.…”

“…Based on a significant correlation between the asymmetry of the thoracic shape and respiratory function, Hirayama et al 1) suggested that the greater the asymmetry of the thoracic shape, the lower the respiratory function. Homma et al 2) and Sano et al 3) also found a significant correlation between the TLD and the asymmetry in the cross-sectional area of the quadratus lumborum and the psoas major. These previous studies suggested that thoracic asymmetry (the TLD and asymmetry of the thoracic shape) causes impaired respiration and motor function by causing asymmetry in the local muscle activity of the trunk.…”

“…Based on previous studies [1][2][3][4] , we expect that thoracic asymmetry causes asymmetry of the IAMF during gait. Although it is necessary to collect data on the disease to apply this hypothesis to clinical practice, it is expected that many factors, such as pain and deformity, may affect the disease outcome.…”

“…Thoracic movement is composed of rib and the thoracic spine movements, which perform important roles in the respiration and postural stability. In recent years, several studies have focused on the thoracic lateral deviation (TLD) and asymmetry of the thoracic shape in the resting position and investigated their relationship with physical function 1 , 2 , 3 , 4 ) . Based on a significant correlation between the asymmetry of the thoracic shape and respiratory function, Hirayama et al 1 ) suggested that the greater the asymmetry of the thoracic shape, the lower the respiratory function.…”