Effects of the Features of Thoracic Shape at Rest on Thoracic Mobility and Respiratory Function

: [Purpose] A three-dimensional image analysis device was used to measure thoracic shape in the horizontal plane to investigate how left/right asymmetry affects thoracic mobility and respiratory function. [Subjects and Methods] The subjects were 20 healthy adult men. A three-dimensional image analysis device was used to create horizontal, cross-sectional views of the upper and lower thorax expiratory levels. The left and right cross-sectional areas were compared. Relationships between left/right ratios of thoracic shape and mobility and respiratory function were investigated. [Results] Comparisons of left/right thorax cross-sectional area ratios revealed left/right asymmetry, with larger left upper and right lower thoraces. Correlations were found between left/right thoracic cross-sectional area ratios, rates of chest expansion, and respiratory function. [Conclusion] Resting expiratory-level thoracic shapes showed left/right asymmetry, with larger left upper and right lower thoraces. The extent of left/right asymmetry in thoracic shape may affect functional activity during respiration and may be reflected in thoracic mobility and respiratory function.