- 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:
- 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.
- Surgical Closure of the Rotator Interval:
- Isolated closure of rotator interval defects for shoulder instability.
- Rotator interval lesion.
- 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.
- The Addition of Rotator Interval Closure After Arthroscopic Repair of Either Ant or Post Shoulder Instability. Effect on Glenohumeral Translation and ROM
- 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
- Biomechanical Analysis Comparing a Traditional Superior-Inferior Arthroscopic RI Closure With a Novel Medial-Lateral Technique in a Cadaveric Multidirectional Instability Model
- Effects of Rotator Interval on Posterior Capsule:
- Letter to the Editor: The Use of Rotator Interval Closure in the Arthroscopic Treatment of Posterior Shoulder Instability
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.
