Fig.1: Oblique sagittal PD MR image shows focal fluid signal intensity at articular surface of the anterior insertion of the supraspinatous tendon. There is bone marrow edema at the site of the insertion.
Fig.2: Coronal T2 MR image with fat suppression confirms similar findings. Partial involvement of the tendon, fluid signal intensity, location (articular side, at tendon insertion) are characteristic of a rim-rent tear of the supraspinatous tendon.
- Partial-thickness tears are common cause of shoulder pain
- Believed to be due to multiple factors including intrinsic degeneration, microtrauma, trauma, hypovascularity and subacromial impingement
- Partial-thickness tear of the supraspinatous tendon can be on the articular or bursal side, at the tendon insertion or at the critical zone
- Critical zone tear is located at 1-2 cm proximal to the cuff tendon insertion on the greater tuberosity, it was once thought to be the most common type of partial-thickness tear
- Partial-thickness tear on the articular side at the tendon insertion on the greater tuberosity
- Considered to be the most common type of partial-thickness tear of supraspinatous tendon
- Can be difficult to visualize on MR imaging because of patient's positioning (too much internal rotation) and it was not well-known to radiologists
- Potential to progress into a full-thickness tear
- Tricks: on coronal images - inspect the leading edge of the supraspinatous tendon just lateral to the bicipital grove; on sagittal images - inspect closely at the insertion of tendons