Scott S H, Engstrom C M, Loeb G E
Department of Physiology, Queen's University, Kingston, Ontario, Canada.
J Anat. 1993 Apr;182 ( Pt 2)(Pt 2):249-57.
A previous investigation suggested that striation patterns spanning individual muscles in longitudinally oriented MR images may represent the orientation of its fascicles. In this study, we confirmed that these striation patterns could be used to infer fascicle orientation and to compute other architectural features of muscles from MR images. The volumes of 14 muscles within a cadaveric thigh were shown to be estimated accurately from cross-sectional MR images by comparison with direct measures from muscle mass. The angles of striations were measured at several positions within vastus medialis and semimembranosus from sagittal and frontal-plane MR images. Mathematical techniques were developed to infer the 3-dimensional orientation of fascicles based on these striation angles. The angle of striations in a 3rd oblique plane was shown to agree with mathematical predictions based on these computed orientations. The pennation angle, defined as the angle between the fascicles and the line of action of the muscle, predicted from the MR images, was similar to directly measured values. Interestingly, the pennation angle of these fascicles varied along the length of the muscle; in vastus medialis, pennation angle ranged from 5 degrees to 50 degrees in a proximodistal direction. Procedures were developed and validated to compute fascicle length by projection of fascicle orientation across the 3D shape of the muscles. The use of MR images to estimate muscle morphometry could improve greatly the predictive capabilities of musculoskeletal modelling by reducing the number of unknown model parameters.
先前的一项研究表明，在纵向取向的磁共振图像中跨越单个肌肉的条纹图案可能代表其肌束的取向。在本研究中，我们证实这些条纹图案可用于推断肌束取向，并从磁共振图像计算肌肉的其他结构特征。通过与肌肉质量的直接测量结果进行比较，显示从尸体大腿内14块肌肉的横截面磁共振图像可以准确估计其体积。从矢状面和额面磁共振图像测量股内侧肌和半膜肌内几个位置的条纹角度。开发了数学技术，以基于这些条纹角度推断肌束的三维取向。结果显示，在第三个斜平面上的条纹角度与基于这些计算取向的数学预测结果一致。从磁共振图像预测的羽角（定义为肌束与肌肉作用线之间的角度）与直接测量值相似。有趣的是，这些肌束的羽角沿肌肉长度变化；在股内侧肌中，羽角在近端到远端方向上从5度到50度不等。开发并验证了通过将肌束取向投影到肌肉的三维形状上来计算肌束长度的程序。使用磁共振图像估计肌肉形态学可以通过减少未知模型参数的数量，极大地提高肌肉骨骼建模的预测能力。
