Subscapularis tendinosis

Subscapularis tendon: Subscapularis tendon tears may occur as a component of massive rotator cuff tears[40,41]. The tendinous part of the subscapularis tendon is the broadest tendon among the rotator cuff and therefore commonly affected by tears and tendinitis.

Subscapularis tendinosis. A: Axial gradient-recalled echo image showing focal high signal within the subscapularis tendon with fibres thickening (arrow); B: Anterior coronal oblique fat-sat T2-weighted image of the same patient showing high signal within the lower fibres of the subscapularis tendon (arrow).

The subscapularis tendon may be affected in isolation in traumatic injury. Subcoracoid impingement, which is a cause of subscapularis degenerative tears, is suspected when the distance between the coracoid process and the lesser tuberosity of the humerus is less than 6 mm on axial MR images. Other reported associated MRI signs include subcortical bone marrow edema of the coracoid process and lesser tuberosity of the huemrus.

Sub-coracoid impingement. A and C: Axial gradient-recalled echo images; B: Axial T1-weighted image showing narrowed coraco-humeral distance (arrows in A) with tapered coracoid process, thickening and abnormal high signal of the subscapularis tendon (asterisk in C).