PT Orthopedic Clinical Specialist (OCS) Clinical Practice Exam

The glenohumeral ligaments tighten at specific positions to limit unwanted translation of the humeral head. In mid-range abduction, around 45–60 degrees, the middle glenohumeral ligament becomes taut to resist anterior translation, and the inferior glenohumeral ligament complex also tightens to provide stability against anterior–inferior translations as the arm moves out from the side. This combination helps stabilize the shoulder during the early to mid ranges of abduction when the head is more prone to anterior shift. The superior ligament, by contrast, is most taut with the arm at the side (0 degrees of abduction) to restrain certain motions there, not in the mid-range. The inferior ligament is not taut uniformly across all ranges but increases tension with greater abduction, especially beyond mid-range. And the ligaments are not all equally taut throughout ROM; each has its own pattern of tension.