- See:
-
Muscular Stabilizers:
-
Static Stabilizers
- Discussion:
- stabilizers include glenohumeral size, posteriorly angulated glenoid &
humeral head, & functional muscle control (most important);
- structure that is most responsible for preventing anterior glenohumeral
dislocation varies with the position of the arm.
- 0 deg:
- at 0 degrees of abduction,
subscapularis muscle stabilizes the
joint to a large extent.
- 45 deg:
- at 45 degrees of abduction subscapularis, middle glenohumeral ligament,
and the anterior superior fibers of
inferior glenohumeral ligament provide
shoulder stability; (greatest strain in the inferior and middle ligaments);
- 90 deg:
- in abduction with external rotation, the
inferior glenohumeral ligament
prevents dislocation;
- when arm is in a position of anterior instability (90 deg abduction &
90 degrees external rotation), role of dynamic stabilizers changes.
- in this position, pectoral, short head of
biceps, coracobrachial,
anterior
deltoid, &
subscapularis
resist
Anterior Dislocation;
Stabilizing mechanisms preventing anterior dislocation of the glenohumeral joint.
SJ Turkel et al.
JBJS. Vol 63-A. 1981. p 1208-1217.
