- See:
Static Stabilizers of the Shoulder
- Rotator Interval Capsule:
- the rotator interval is a triangular portion of shoulder capsule which lies between the
supraspinatus and
subscapularis tendons;
- capsular anatomy:
- interval capsule is reinforced by the superior glenohumeral and coracohumeral ligaments;
-
superior glenohumeral ligaments:
- has two sites of origin: supraglenoid tubercle - just anterior to long head of biceps origin on superior labrum and the base of coracoid;
- arthroscopically it may be hidden by the biceps tendon;
- inserts on proximal aspect of
lesser tuberosity;
- at 0 deg abduction, superior & MGHL develops most strain, and together w/ the coracohumeral ligament stabilize the shoulder in adduction;
- it helps to prevent posterior and inferior instability;
- references:
-
Tensile properties of the superior glenohumeral and coracohumeral ligaments.
-
coacohumeral ligament:
- arises as an extraarticular ligament on the lateral surface of coracoid and inserts into the greater and lesser tuberosities,
spanning the bicipital groove;
- sectioning of coracohumeral ligaments produces anteroinferior instability;
- represents folded thickening of glenohumeral capsule in area of rotator interval between subscapularis & supraspinatus;
- w/ body upright & arm in dependent position, coracohumeral & MGHL play important roles in resisting inf translation.
- references:
- The structure and function of the coracohumeral ligament.
An anatomic and microscopic study. J. Shoulder Elbow Surg. 1993. p 70-77.
-
Tensile properties of the superior glenohumeral and coracohumeral ligaments.
- acts to limit flexion and external rotation;
- tears of the rotator interval capsule:
- may mimic rotator cuff tears;
- impingment signs may be present along w/ biceps tendon tenderness;
- may allow
extravasation of dye into subacromial space, as well as the subscapularis fossa (w/ dye seen anterior to the subscapularis);
- leakage into the subscapularis fossa may require shoulder movement;
- in the study by
Harryman et al, the authors report that sectioning of the rotator interval capsule allowed
50% posterior translation and 100% inferior translation;
- management:
- in cadaver experiments, imbrication of interval capsule helped to eliminate posterior and inferior instability;
- note, however, if the superior capsular structures are shortened w/o addressing the redundancy of the inferior capsule, may tend
to push the humeral head inferiorly;
- references:
-
Rotator interval lesion.
- The role of the rotator interval capsule in passive motion and stability of the shoulder. DT Harryman II et al. JBJS. vol 74, 1992. p 53-66.
-
The anatomy and histology of the rotator interval capsule of the shoulder.
-
Isolated closure of rotator interval defects for shoulder instability.
-
Arthroscopic treatment of anterior-inferior glenohumeral instability. Two to five-year follow-up.
-
Thermal versus suture treatment of symptomatic capsular laxity.
-
Arthroscopic rotator interval repair in glenohumeral instability: description of an operative technique.
-
The effects of thermal capsulorrhaphy and rotator interval closure on multidirectional laxity in the glenohumeral joint: A cadaveric biomechanical study.
Stabilizing mechanism preventing anterior dislocation of GHJ.
J Bone Joint Surg 1981;63A:1208. Turkel SJ, Panio MW, Marshall JL:
Capsular ligaments of the shoulder. Anatomical and functional study of the anterior superior capsule.
Year Book: Anterior Capsulolabral Reconstruction of the Shoulder in Athletes in Overhand Sports.
Capsular restraints to anterior-posterior motion of the abducted shoulder: A biomechanical study.
SJ O'Brien et al.
J. Shoulder Elbow Surgery.
Vol 4. 1995. p 298-308.
The Vascular Anatomy of the Glenohumeral Capsule and Ligaments: An Anatomic Study.
