Dumas R, Cheze L, Fayet M, Rumelhart C, Comtet J-J
UMRT9406, laboratoire de biomécanique et mécanique des Chocs, INRETS, bâtiment Oméga, 43, boulevard du 11-Novembre-1918, 69622 Villeurbanne, France.
Chir Main. 2008 Oct;27(5):195-201. doi: 10.1016/j.main.2008.08.008. Epub 2008 Sep 7.
In order to define the movements of a joint, clinicians usually use anatomic terms. These terms are clearly understandable for a simple movement, defined in an anatomic plane. However, these terms are ambiguous for complex movements or for movements out of an anatomic plane. This, for instance, is the case for the internal-external axial rotation of the trapezometacarpal joint. For the study of complex movements, engineers preferentially use methods such as Euler angles, which correspond to three angles about three axes chosen in a defined order or sequence. Thus, the International Society of Biomechanics has proposed a joint coordinate system definition where every axis is associated with a functional degree of freedom of the joint. The first and third axes are embedded in the proximal and distal segments whilst the second axis, called the "floating" axis, is always orthogonal to the other two. The present work deals with the application of this concept to the trapezometacarpal joint. The two principal degrees of freedom, of flexion-extension and of abduction-adduction are defined following classical anatomical axes of respectively the trapezium and first metacarpal. Conversely, internal-external axial rotation is defined about the "floating" axis which does not have anatomical definition but can be geometrically deduced from the two others.
为了定义关节的运动，临床医生通常使用解剖学术语。对于在解剖平面中定义的简单运动，这些术语很容易理解。然而，对于复杂运动或超出解剖平面的运动，这些术语就含糊不清了。例如，大多角掌指关节的内外轴向旋转就是这种情况。对于复杂运动的研究，工程师们优先使用诸如欧拉角之类的方法，这些方法对应于围绕按定义的顺序或序列选择的三个轴的三个角度。因此，国际生物力学学会提出了一种关节坐标系定义，其中每个轴都与关节的一个功能自由度相关联。第一轴和第三轴分别嵌入近端和远端节段，而第二轴，即所谓的“浮动”轴，始终与其他两轴正交。本研究工作探讨了这一概念在大多角掌指关节中的应用。屈伸和内收外展这两个主要自由度是分别按照大多角骨和第一掌骨的经典解剖轴来定义的。相反，内外轴向旋转是围绕“浮动”轴定义的，该轴没有解剖学定义，但可以从其他两个轴几何推导得出。
