Brown Stephen H M, McGill Stuart M
Department of Kinesiology, University of Waterloo, Waterloo, ON, Canada.
Spine (Phila Pa 1976). 2009 Jan 15;34(2):E70-5. doi: 10.1097/BRS.0b013e31818bd6b1.
In situ testing of the rat abdominal wall.
To test the ability of muscularly generated force and stiffness to be transmitted between the layers of the abdominal wall.
The abdominal wall is comprised of 3 obliquely oriented sheet-like muscles bound together through a connective tissue network. This anatomic arrangement would seem ideal to facilitate myofascial force transmission, which if present would indicate shear connections between the muscle layers that could have important mechanical consequences.
In 10 Sprague-Dawley rats, the 3 layers of the abdominal wall were isolated together and attached to a servomotor force/displacement system. The abdominal wall was stimulated via electrodes over the surface of the transverse abdominis, and measures of force and stiffness were obtained. The aponeurosis attaching the transverse abdominis to the rectus sheath was then cut and the wall was restimulated and the same measures were again obtained.
Active force and stiffness were both reduced in the cut aponeurosis state. These drops were much lower (10.6% and 10.7%, respectively) than would be expected if the transverse abdominis were completely removed. Furthermore, a control group (5 rats), in which the aponeurosis was not cut, but a similar amount of time to that necessary to perform the aponeurosis surgery was allowed to elapse, showed reductions in active force and stiffness (7.9 and 8.2, respectively) nearing that seen in the cut state. This indicates that at least a portion of this drop was due to the passage of time in the compromised surgical state.
It was concluded that the majority of the force and stiffness generated by the transverse abdominis was transferred through the connective tissue network adhering to the internal oblique muscle. This indicates the presence of strong shear connections between the muscular layers, which suggests a composite stiffening function of the architectural design.
大鼠腹壁的原位测试。
测试肌肉产生的力量和刚度在腹壁各层之间传递的能力。
腹壁由3层斜向排列的片状肌肉通过结缔组织网络结合在一起组成。这种解剖结构似乎非常有利于肌筋膜力量的传递，如果存在这种传递，则表明肌肉层之间存在剪切连接，这可能会产生重要的力学后果。
在10只Sprague-Dawley大鼠中，将腹壁的3层一起分离并连接到伺服电机力/位移系统。通过在腹横肌表面的电极刺激腹壁，并获取力量和刚度的测量值。然后切断连接腹横肌和腹直肌鞘的腱膜，再次刺激腹壁并再次获取相同的测量值。
在腱膜切断状态下，主动力和刚度均降低。这些下降幅度（分别为10.6%和10.7%）远低于腹横肌完全切除时预期的下降幅度。此外，一个对照组（5只大鼠），其中腱膜未切断，但经过了与腱膜手术所需时间相似的时间，其主动力和刚度的下降（分别为7.9和8.2）接近切断状态下的下降幅度。这表明至少部分下降是由于手术状态受损导致的时间推移。
得出的结论是，腹横肌产生的大部分力量和刚度是通过附着于腹内斜肌的结缔组织网络传递的。这表明肌肉层之间存在强大的剪切连接，这提示了这种结构设计具有复合强化功能。
