Wuelker N, Plitz W, Roetman B, Wirth C J
Department of Orthopedics, Hannover Medical School, Germany.
Acta Orthop Scand. 1994 Aug;65(4):442-6. doi: 10.3109/17453679408995490.
We evaluated the function of the supraspinatus tendon with a dynamic shoulder model. Active glenohumeral joint motion was simulated in 10 cadaveric shoulder specimens with hydrodynamic cylinder forces at the deltoid muscle and at the rotator cuff. Computerized regulation initiated standardized cycles of glenohumeral joint motion, where the isolated effect of the supraspinatus muscle could be studied. The efficacy of the supraspinatus muscle on elevation of the glenohumeral joint was measured with an ultrasonic sensor system. Pressures underneath the coracoacromial vault were recorded with capacitive sensors, as an indicator of the impingement at the shoulder. Elimination of force of the supraspinatus muscle led to a 6 percent decrease in elevation of the glenohumeral joint. The deltoid muscle was able to reverse this loss of elevation by a force increase of one third of the lost supraspinatus force. If no force was applied to the supraspinatus muscle, average pressures underneath the coracoacromial vault decreased 8 percent. It was concluded that the supraspinatus produces less torque and more glenohumeral joint compression than the deltoid. However, the supraspinatus has no effect on depression of the humeral head during elevation. The clinical consequence of our observations is that operative closure of supraspinatus tendon defects is not mandatory.
我们使用动态肩部模型评估了冈上肌腱的功能。在10个尸体肩部标本中，通过在三角肌和肩袖处施加流体动力缸力来模拟肱盂关节的主动运动。计算机化调节启动了肱盂关节运动的标准化周期，在此周期中可以研究冈上肌的单独作用。使用超声传感器系统测量冈上肌对肱盂关节抬高的功效。用电容式传感器记录喙肩穹顶下方的压力，作为肩部撞击的指标。消除冈上肌的力量会导致肱盂关节抬高降低6%。三角肌能够通过将力量增加至失去的冈上肌力量的三分之一来逆转这种抬高损失。如果不向冈上肌施加力量，喙肩穹顶下方的平均压力会降低8%。得出的结论是，与三角肌相比，冈上肌产生的扭矩较小，肱盂关节压缩力较大。然而，冈上肌在抬高过程中对肱骨头的下压没有影响。我们观察结果的临床意义是，冈上肌腱缺损的手术闭合并非必需。
