- Rotator Interval Capsule:
- rotator interval is a triangular portion of shoulder capsule which lies between the supraspinatus and subscapularis tendons;
- capsular anatomy: (Static Stabilizers / Capsule of the Shoulder)
- interval capsule is reinforced by the superior glenohumeral and coracohumeral ligaments;
- references:
- Capsular ligaments of the shoulder. Anatomical and functional study of the anterior superior capsule.
- Capsular restraints to anterior-posterior motion of the abducted shoulder: a biomechanical study.
- The Vascular Anatomy of the Glenohumeral Capsule and Ligaments: An Anatomic Study.
- Static capsuloligamentous restraints to superior-inferior translation of the glenohumeral joint.
- The role of the rotator interval capsule in passive motion and stability of the shoulder.
- 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;
- reference:
- 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.
- 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;
- 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;
- if 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.
- 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 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.
- Arthroscopic rotator interval closure in shoulder instability repair: A retrospective study
- effects on multidirectional instability:
- Biomechanical analysis comparing a traditional superior-inferior arthroscopic rotator interval closure with a novel medial-lateral technique in a cadaveric multidirectional instability model.
- Effects of Capsular Plication and Rotator Interval Closure in Simulated Multidirectional Shoulder Instability
- The effects of thermal capsulorrhaphy and rotator interval closure on multidirectional laxity in the glenohumeral joint: a cadaveric biomechanical study.
- 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