- 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 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.
The role of the rotator interval capsule in passive motion and stability of the shoulder. J Bone Joint Surg Am 1992;74:53-66.
Static capsuloligamentous restraints to superior-inferior translation of the glenohumeral joint. Am J Sports Med 1992;20:675-685.
The Addition of Rotator Interval Closure After Arthroscopic Repair of Either Anterior or Posterior Shoulder Instability. Effect on Glenohumeral Translation and Range of Motion
Arthroscopic Rotator Interval Closure. Effect of Sutures on Glenohumeral Motion and Anterior-Posterior Translation
Effects of Capsular Plication and Rotator Interval Closure in Simulated Multidirectional Shoulder Instability
