Tangent sign of supraspinatus muscle belly atrophy

Last revised by Henry Knipe on 7 May 2024

The tangent sign is useful in helping to quantify supraspinatus muscle belly 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 most medial coracoid process 1-3.

  • negative sign: normal muscle belly lies above the line 1-3

  • positive sign: abnormal small muscle belly from atrophy lies below the line 1-3

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