下腿底屈筋群の筋構成に関する簡易計測法の開発

抄録

  Major differences in histological, anatomical and physiological characteristics exist between the gastrocnemius and soleus muscles. The authors calculated the girth and subcutaneous fat thickness at the belly portion (G portion) and the musculotendinous junction portion (S portion) of the medial gastrocnemius, and then devised a method of calculating the ratio of gastrocnemius cross-sectional area to that of the other plantar flexors. The necessary parameters for the calculation were identified based on the analysis of the CT images of these portions. Consequently, the following findings were obtained. 1) The cross-sections of both portions could be approximated to a circle, and the subcutaneous thickness in each portion represented the average of all points along the circumference. 2) At G and S, the fat-free cross-sectional area excluding the gastrocnemius varied at a constant ratio. 3) The ratio of fat-free cross-sectional area excluding the gastrocnemius at G to the cross-sectional area of other plantar flexors showed small individual differences. These findings indicate that the girth and subcutaneous fat thickness measured at S and G may provide a relatively precise estimate of the ratio of gastrocnemius cross-sectional area to that of the other plantar flexors.