Glenohumeral joint stability. Selective cutting studies on the static capsular restraints.

The glenohumeral joint relies on static and dynamic contributions of the local soft tissues to maintain joint stability. Dynamic stabilizers consist of the local musculature (the rotator cuff and periscapular muscles), whereas static stabilizers include the glenoid labrum and associated capsuloligamentous components. The functional interaction of static and dynamic components is complex and not completely understood. Selective cutting studies have been done to define the effect of sectioning various static components on resultant glenohumeral translation. These studies have played a pivotal role in the understanding of static factors controlling shoulder stability: the anatomic variability in capsuloligamentous anatomy has been recognized, and the complex interaction among various regions of the shoulder capsule and their labral attachment sites has been shown. Additionally, it has been recognized that the function of the capsuloligamentous restraints is highly dependent on arm position.