Zocchi L, Garzaniti N, Newman S, Macklem P T
J Appl Physiol (1985). 1987 Apr;62(4):1655-64. doi: 10.1152/jappl.1987.62.4.1655.
We tested the hypothesis that the mechanical arrangement of costal (COS) and crural (CRU) diaphragms can be changed from parallel to series when direct or indirect transmission of tension occurs. Ratio of rib cage to abdominal displacement (RC/AB) resulting from separate COS and CRU stimulations were used to measure RC expanding action. Hyperinflation in six dogs caused RC/AB with COS and CRU stimulations to change progressively from 0.53 +/- 0.07 (SE) and 0.03 +/- 0.05 at functional residual capacity (FRC) to -0.48 +/- 0.08 and -0.46 +/- 0.05 at 68% inspiratory capacity, respectively. Liquid substitution of abdominal contents in six other dogs equalized abdominal pressure swings (delta Pab), without changing chest wall elastic properties or geometry, or costal RC/AB (0.35 +/- 0.07 before and 0.33 +/- 0.06 after) but caused crural RC/AB to change from 0.01 +/- 0.05 to 0.31 +/- 0.01. We conclude that hyperinflation changes fiber orientation, allowing direct transmission of tension between COS and CRU, which become linked mechanically in series (the diaphragm acts as a unit with RC deflating action); and equalization of delta Pab causes indirect transmission of tension between COS and CRU, which become linked in series (the diaphragm acts as a unit with RC inflating action).
当出现张力的直接或间接传递时，肋部（COS）和膈脚部（CRU）膈肌的机械排列可从平行变为串联。通过分别刺激COS和CRU所产生的胸廓与腹部位移之比（RC/AB）来测量胸廓扩张作用。对6只狗进行肺过度充气时，刺激COS和CRU所产生的RC/AB分别从功能残气量（FRC）时的0.53±0.07（标准误）和0.03±0.05逐渐变化为吸气量68%时的-0.48±0.08和-0.46±0.05。对另外6只狗进行腹腔内容物液体替代，使腹部压力波动（ΔPab）达到平衡，同时不改变胸壁弹性特性或几何形状，以及肋部RC/AB（之前为0.35±0.07，之后为0.33±0.06），但导致膈脚部RC/AB从0.01±0.05变为0.31±0.01。我们得出结论：肺过度充气会改变纤维方向，使张力在COS和CRU之间直接传递，二者在机械上串联相连（膈肌作为一个整体发挥作用，使胸廓回缩）；而ΔPab达到平衡会使张力在COS和CRU之间间接传递，二者串联相连（膈肌作为一个整体发挥作用，使胸廓扩张）。
