Variation of internal impingement --> lesser tuberosity abuts superior pole of glenoid Standard non-contrast sequences (Image 1) show a non-acute longitudinal partial tear of subscapularis, thickened high-attaching anterior band of IGHL, subtle evidence of SLAP tear at posterosuperior glenoid rim (including a tiny perilabral cyst), and insertional tendinosis involving infraspinatus & teres minor.
However, an isotropic 3D acquisition (SPACE) obtained in the position of pain (ABER) revealed the mechanism of injury --> multiplanar reformations clearly showed the lesser tuberosity (NOT the greater tuberosity) directly abutting and displacing the superior glenoid labrum with an associated SLAP tear confirmed by distension of the associated perilabral cyst and the split tear of subscapularis also extending from the site of impingement !
Note the GHJ position at left shoulder at the top of the backswing is actually Abduction and Internal Rotation (ABIR) together with cross-body flexion (Image 3).
This case illustrates several things:
1. Internal shoulder impingement can involve lesser tuberosity rather than greater tuberosity (I have not seen this previously reported);
2. The importance of imaging a joint in the position of pain;
3. The power of isotropic volumetric scan techniques --> although these require a good 3D workstation to fully comprehend the data !