Mallon W J, Herring C L, Sallay P I, Moorman C T, Crim J R
Triangle Orthopaedic Associates, Durham, NC 27704, USA.
J Shoulder Elbow Surg. 1996 Jul-Aug;5(4):299-306. doi: 10.1016/s1058-2746(96)80057-7.
Internal rotation of the shoulder is frequently measured by noting the maximal vertebral level reached by the patient's thumb, but it is not at all certain that this maneuver is strictly measuring internal rotation. We analyzed this maneuver with computed tomographic scans of the shoulder in differing positions. We also analyzed extension of the glenohumeral joint and scapulothoracic articulation with scapular lateral radiographs. Finally, we used posteroanterior radiographs to analyze elbow flexion at the limits of internal rotation behind the back. We found that maximal internal rotation behind the back occurs in approximately a 2 : 1 ratio between the glenohumeral joint and the scapulothoracic articulation. However, the scapulothoracic articulation was more significant in placing the arm behind the back, whereas the glenohumeral joint performed most of the internal rotation in front of the body. The scapulothoracic articulation assists in this motion by both extension and internal rotation of the scapula on the thorax. The limits of internal rotation behind the back are reached with a significant contribution from elbow flexion. We conclude that measuring shoulder internal rotation by the maximal vertebral level reached by the patient's thumb greatly oversimplifies the concept of internal rotation and that limitations in this motion may not be strictly due to a loss of internal rotation at the glenohumeral joint.
肩部内旋通常通过记录患者拇指所能触及的最高椎体水平来测量，但这种操作是否严格测量了内旋并不确定。我们通过对处于不同位置的肩部进行计算机断层扫描来分析这种操作。我们还通过肩胛外侧位X线片分析了盂肱关节和肩胛胸壁关节的伸展情况。最后，我们使用前后位X线片来分析背部后方内旋极限时的肘关节屈曲情况。我们发现，背部后方的最大内旋在盂肱关节和肩胛胸壁关节之间的比例约为2:1。然而，肩胛胸壁关节在将手臂置于背部后方时更为重要，而盂肱关节在身体前方进行了大部分的内旋。肩胛胸壁关节通过肩胛骨在胸廓上的伸展和内旋来辅助这一动作。背部后方内旋的极限是在肘关节屈曲的显著作用下达到的。我们得出结论，通过患者拇指所能触及的最高椎体水平来测量肩部内旋极大地简化了内旋的概念，并且这种动作的限制可能并不完全是由于盂肱关节内旋丧失所致。
