Image Interpretation: Focal, anechoic disruption of the interstitial fibers of the right supraspinatus tendon with possible extension to the articular surface, which measures approximately 0.32 cm x 0.46 cm x 0.15 cm. No cortical irregularity noted along the greater tuberosity. The subacromial bursa is not distended or thickened. On dynamic assessment, no bunching or distention of the subacromial bursa is noted. The biceps tendon is normal. No tendon sheath effusion is noted. The subscapularis is normal. The infraspinatus is normal. No fatty atrophy of the rotator cuff muscles. No effusion is noted in the posterior glenohumeral joint. Sonopalpation along the supraspinatus tendon reproduced the pain. Impression: Incomplete, partial thickness, interstitial tear within the belly of the supraspinatus tendon measuring approximately 0.32cm x 0.46cm x 0.15 cm.

Teaching Pearl: Degenerative rotator cuff tears can present with insidious pain worsened by overhead activity, and partial-thickness tears may be challenging to diagnose than full-thickness tears. A focused scan should inspect the bursal surface, articular surface, and interstitial tendon for focal hypoechoic or anechoic defects, tendon thinning, and loss of fibrillar architecture. If symptoms, weakness, or surgical planning questions exceed what ultrasound can define, MRI or MR arthrography may be appropriate. References: 1.Farooqi AS, Lee A, Novikov D, et al. Diagnostic accuracy of ultrasonography for rotator cuff tears: a systematic review and meta-analysis. Orthop J Sports Med. 2021;9(10):23259671211035106. doi:10.1177/23259671211035106 2. Roy JS, Braen C, Leblond J, et al. Diagnostic accuracy of ultrasonography, MRI and MR arthrography in the characterisation of rotator cuff disorders: a systematic review and meta-analysis. Br J Sports Med. 2015;49(20):1316-1328. doi:10.1136/bjsports-2014-094148 3. Expert Panel on Musculoskeletal Imaging; Nacey N, Fox MG, Blankenbaker DG, et al. ACR Appropriateness Criteria chronic shoulder pain: 2022 update. J Am Coll Radiol. 2023;20(5S):S49-S69. doi:10.1016/j.jacr.2023.02.017