Figure 13b. Rotator interval. (a) Oblique coronal T2-weighted MR image shows the biceps tendon (straight arrows) coursing just anterior to the supraspinatus tendon and capsule (curved arrows). The interface between these two structures is hyperintense fluid. (b) Coronal (longitudinal) US image shows a normal, hypoechoic fluid interface between the biceps tendon (straight arrows) and the anterior edge of the supraspinatus tendon (curved arrows).