Rotator Interval Anatomy
- The RI is a triangle shaped region between the supraspinatus and supscapularis tendons. The base is the coracoid process. The apex is the intertubercular groove. The inferior border is the superior aspect of the subscapularis tendon. The superior border is the anterior aspect of the supraspinatus tendon.
- Contents of RI = long head of biceps tendon, superior glenohumeral ligament, glenohumeral capsule, and the coracohumeral ligament. (Bennett WF, Arthroscopy 2001;17:101)
- Rotator interval release leds to dislocaiton in 50% of specimens (occurs in 60° of abduction and external roation. (Fitpatrick MJ, Arthroscopy 2003;19(suppl1):70).
- Cole BJ, CORR 2001;390:129
Rotator Interval Xray
- MRI arthrogram is indicated to evaluate any rotator interval pathology
Rotator Interval Clinical Evaluation
- Rotator interval laxity is assessed by external rotating the humerus during the sulcus sign. If sulcus fails to improve with ER, the rotator interval is incompetent.
Rotator Interval Classification / Treatment
- Rotator Interval Contracture: associated with adhesive capsulitis. C/O pain and limited active and passive ROM. See Adhesive capsulitis
- Rotator Interval Laxity: leads to posteroinferior shoulder instability, positive sulcus sign. Rotator interval closure best eliminates a positive sulcus sign. (Field LD, AJSM 1995;23:557).
- Rotator Interval closure leads to significant reduction in posteroinferior translation of the humerus on the glenoid. (Harryman DT II, JBJS 1992;74A:53).
Rotator Interval Review References
- Fitzpatrick MJ, Arthroscopy, 2003;19:70
- Hunt SA, JAAOS 2007;15:218