Tangent sign

The tangent sign is useful in helping to quantify supraspinatus muscle belly fatty atrophy with a positive sign implicated with a poorer outcome after supraspinatus tendon tear repair.

On a sagittal oblique plane, a line is drawn between the upper surface of the scapular spine and the upper surface of the coracoid process (medial aspect). A normal supraspinatus muscle belly lies above this line (negative sign) and an abnormal supraspinatus muscle belly (small from fatty atrophy) lies below this line (positive sign) .

See also