What is the significance of a positive tangent sign or fatty degeneration?
Atrophy and fatty degeneration aim to assess the chance for the muscle to recover. Significant atrophy and fatty degeneration are signs for irreversible damage and a good functional outcome after cuff repair cannot be expected.
Key findings:
- full-thickness/transmural tear of the distal supraspinatus tendon (red arrow) with increased fluid in the subacromial/subdeltoid bursa (blue arrowhead)
- mediolateral and anteroposterior diameter (purple measurement)
- posterior extension into the anterosuperior part of the infraspinatus tendon (orange arrow)
- mild long head biceps tendinosis (red arrowhead)
- small anterior acromial spur (green arrow)
Supraspinatus atrophy and fatty degeneration:
no signs of atrophy
- negative tangent sign: the supraspinatus muscle belly is cut by a tangent from the base of the coracoid process to the superior margin of the scapular spine 7,
- the cross-sectional area of the supraspinatus muscle (blue) compared to the cross-sectional area of the supraspinatus fossa (red) 1,3,9 is more than 50% in this case
no fatty degeneration as per Goutallier classification 8