Pathogenesis:
Multifactoral - extrinsic and intrinsic
Extrinsic mechanism: Repitative microtrauma, Subacromial impingement, Macrotrauma - uncommon
Intrinsic mechanism: debatable change in vascularity
Important to remember:
Supraspinatus tendon is primarily involved in most
Tears usually begin near rotator interval
Partial tears are common on the articular surface
Subscapularis tears:
MR (both conventional and arthrographic) are not sensitive in the diagnosis of the articular surface partial thickness tears. (Sensitivity of noncontrast MRI - 40%, and MR arthrography - 36% - reference)
References:
Seibold C et al. Rotator Cuff: Evaluation with US and MR Imaging. Radiographics. 1999;19:685-705
