MSK ultrasound of the rotator interval
This article summary explains the anatomy of the rotator cuff interval, an important stabilizing mechanism which can be compromised in case of adhesive capsulitis. The summary also explains how to scan the rotator interval with MSK ultrasound, interesting for diagnostic and interventional purposes.
The rotator interval is that portion of the shoulder joint where the rotator interval capsule is reinforced externally by the coracohumeral ligament (CHL) and internally by the superior glenohumeral ligament (SGHL) and traversed by the intra-articular biceps tendon. It is a triangular anatomic area in the anterosuperior aspect of the shoulder, which is defined by the coracoid process at its base, superiorly by the anterior margin of the supraspinatus tendon, and inferiorly by the superior margin of the subscapularis tendon. The rotator interval capsule is the antero-superior aspect of the glenohumeral joint capsule, which merges with the CHL and SGHL insertions medial and lateral to the bicipital groove, maintaining the biceps tendon within the groove.
To perform the MSK ultrasound visualization of the rotator interval: The patient is sitting uprights with it’s shoulder is slightly extended and the elbow flexed to facilitate visualization of the rotator interval anteriorly. The transducer is placed transverse over the anterior shoulder and a long-axis view of the rotator interval, with the biceps at the center of image and supraspinatus and subscapularis to either side, is obtained. The CHL is seen draped superiorly over the biceps tendon. Contracture and thickening of the CHL is a frequent finding in adhesive capsulitis.
> From: Yoong et al., Skeletal Radiol 44 (2015) 703–708. All rights reserved to ISS. Click here for the Pubmed summary.