Correlation of the Rotator Interval on Direct CT Arthrography in Shoulder Instability Patients with External Rotation Stress Radiographs

Abstract

The rotator interval (RI) is defined as the space between the anterior aspect of the supraspinatus tendon (SST) and superior aspect of the subscapularis tendon (SSC), covered by rotator interval capsule (RIC) (1, 2). It represents a region of capsule that is not reinforced by overlying rotator cuff tendon (1) and its components, coracohumeral ligament (CHL) and superior glenohumeral ligament (SGHL), are suggested to have a role in glenohumeral joint (GHJ) stability. The role of different shoulder stabilizers vary according to different shoulder position. For example, the CHL is shown to be a stabilizer in superior-inferior directions with arm in external rotation, whereas, the intra-articular pressure that is maintained by the intact RIC is suggested to act as a stabilizer in superior-inferior directions with the arm in internal and neutral rotations (3). The role of the RI in shoulder mechanopathology remains a much debated subject, with some authors advocating its role as a negative articular pressure inducer (3), whereas others, in resisting posteroinferior glenohumeral translation (4-7). Correlation of the Rotator Interval on Direct CT Arthrography in Shoulder Instability Patients with External Rotation Stress Radiographs 견관절 불안정 환자의 CT 관절 조영술상 회전근개 간격과 외회전 부하 영상과의 연관성