Graichen H, Hinterwimmer S, von Eisenhart-Rothe R, Vogl T, Englmeier K-H, Eckstein F
Research Group for Kinematics and Biomechanics, Department of Orthopedic Surgery, University of Frankfurt, Marienburgstr. 2, 60528 Frankfurt, Germany.
J Biomech. 2005 Apr;38(4):755-60. doi: 10.1016/j.jbiomech.2004.05.020.
It is currently unknown in which ways activity of the ab- and adductor shoulder muscles affects shoulder biomechanics (scapular kinematics and glenohumeral translation), and whether these changes are relevant for alterations of the subacromial space width. The objective of this experimental in vivo study was thus to test the hypotheses that potential changes of the subacromial space width (during antagonistic muscle activity) are caused by alterations of scapular kinematics and/or glenohumeral translation. The shoulders of 12 healthy subjects were investigated with an open MRI-system at 30 degrees, 60 degrees, 90 degrees, 120 degrees and 150 degrees of arm elevation. A force of 15N was applied to the distal humerus, once causing isometric contraction of the abductors and once contraction of the adductors. The scapulo-humeral rhythm, scapular tilting and glenohumeral translation were calculated from the MR image data for both abducting and adducting muscle activity. Adducting muscle activity led to significant increase of the subacromial space width in all arm positions. The scapulo-humeral rhythm (2.2-2.5) and scapular tilting (2-4 degrees) remained relatively constant during elevation, no significant difference was found between abducting and adducting muscle activity. The position of the humerus relative to the glenoid was, however, significantly (p < 0.05) different (inferior and anterior) for adducting versus abducting muscle activity in midrange elevation (60-120 degrees). These data show that the subacromial space can be effectively widened by adducting muscle activity, by affecting the position of the humerus relative to the glenoid. This effect may be employed for conservative treatment of the impingement syndrome.
目前尚不清楚肩部内收肌和外展肌的活动以何种方式影响肩部生物力学（肩胛骨运动学和盂肱关节平移），以及这些变化是否与肩峰下间隙宽度的改变相关。因此，本体内实验研究的目的是检验以下假设：肩峰下间隙宽度的潜在变化（在拮抗肌活动期间）是由肩胛骨运动学和/或盂肱关节平移的改变引起的。使用开放式MRI系统对12名健康受试者的肩部在手臂抬高30度、60度、90度、120度和150度时进行了研究。向肱骨远端施加15N的力，一次引起外展肌的等长收缩，一次引起内收肌的收缩。根据MR图像数据计算外展和内收肌活动时的肩肱节律、肩胛骨倾斜度和盂肱关节平移。内收肌活动导致在所有手臂位置时肩峰下间隙宽度显著增加。在抬高过程中，肩肱节律（2.2 - 2.5）和肩胛骨倾斜度（2 - 4度）保持相对恒定，外展和内收肌活动之间未发现显著差异。然而，在中等抬高范围（60 - 120度）内，内收肌与外展肌活动相比，肱骨相对于关节盂的位置存在显著（p < 0.05）差异（向下和向前）。这些数据表明，通过影响肱骨相对于关节盂的位置，内收肌活动可有效增宽肩峰下间隙。这种效应可用于保守治疗撞击综合征。
