The glenohumeral joint achieves tremendous range of
motion. It is a major feat to maintain joint stability throughout
the entire range of motion. However, there are varying
degrees of stabilization dependent on the position of the
humeral head in relation to the glenoid. These stabilizers are
categorized as passive and active. 11 Passive stabilizers
include glenohumeral conformity, small joint volume, adhesion/
cohesion, scapular inclination, as well as ligamentous
and capsular restraints. Active stabilization is achieved by
the long head of the biceps and by the muscles of the rotator
cuff. Normally, there is complex interplay between all of
these stabilizing forces.12 This results in a shoulder joint that
is resistant to subluxation (Figure 1).