Rotator cable at MR imaging: considerations on morphological aspects and biomechanical role

The rotator cable (RC) is a thickening of the coracohumeral ligament. It extends from the coracohumeral ligament to the inferior border of the infraspinatus tendon, with fibres running perpendicularly to the rotator cuff fibres. According to some authors, the RC tends to thicken with age, thus allowing some individuals with a cuff lesion to preserve normal shoulder function. We evaluated the RC with magnetic resonance (MR) imaging and investigated its possible role in the biomechanics of the shoulder affected by cuff lesions.

Between November 2007 and May 2008, we performed shoulder MR examinations for shoulder pain or disability on 94 patients (46 males, 48 females; age range 16-79 years; mean age 54.09 ± 15.09 years) for a total of 104 shoulders (62 right, 42 left).

RC was more easily detectable in oblique coronal scans where it appeared as a crescent-shaped, regularly marginated structure adjacent to the articular surface of the supraspinatus tendon and medial to the insertion point of this tendon on the greater tuberosity. Its thickness was 2.8 ± 0.3 mm. The structure was identified in 62% of cases (mean patient age 55.3 ± 14.9 years). No statistically significant difference in age was found between patients with and without evidence of RC (Student's t test=0.05; p=0.82). Among patients with partial- or full-thickness supraspinatus tendon lesions at MR imaging, no statistically significant difference was found between the presence or absence of RC and disability on Jobe's test (χ(2)=1.17; p>0.05).

RC can be observed at MR imaging in >60% cases. In our sample it did not seem to influence shoulder function in patients with cuff lesions.