OBJECTIVE The purpose of this study is to describe the MRI findings and evaluate the prevalence of supraspinatus myotendinous injuries. MATERIALS AND METHODS Among 1001 consecutive shoulders that underwent either conventional MRI or MR arthrography between January and December 2016, 843 shoulders were included. All MR images were retrospectively analyzed for identification and classification into the appropriate grade of acute or chronic rotator cuff myotendinous injuries. Other MRI findings, such as the presence of rotator cuff tendon insertional tears, and clinical information were also evaluated. RESULTS At MRI, 0.47% (4/843) of shoulders had supraspinatus myotendinous injuries involving the anterior muscular bundle exclusively. Chronic grade III (n = 2), acute grade III (n = 1), and acute grade II (n = 1) injuries were identified in three men and one woman (mean age, 44 years) with a clinical history of trauma (n = 2) or of progressive shoulder pain (n = 2). A concurrent supraspinatus insertional tendon tear with either partial (n = 1) or full (n = 1) thickness was present in half the cases. Loss of tension of the myotendinous junction in grade III myotendinous junction injuries led to severe atrophy and fatty infiltration of the anterior supraspinatus. CONCLUSION Supraspinatus myotendinous junction injuries are uncommon at MRI. These lesions invariably involve the anterior bundle of the supraspinatus muscle and may occur with a concomitant insertional tendon tear. High-grade chronic injuries lead to selective atrophy and fatty infiltration of the anterior supraspinatus muscle.

中文翻译：

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Supraspinatus肌强直结节损伤：MRI表现和患病率。

目的本研究的目的是描述MRI表现并评估棘上肌强直性损伤的患病率。材料与方法在2016年1月至2016年12月间接受常规MRI或MR关节造影的1001个连续肩中，包括843个肩。回顾性分析所有MR图像，以识别和分类为急性或慢性肩袖肌腱损伤的适当等级。还评估了其他MRI表现，例如是否存在肩袖肌腱插入撕裂和临床信息。结果在MRI上，0.47％（4/843）的肩膀遭受了仅累及前肌束的棘上肌强直性损伤。慢性III级（n = 2），急性III级（n = 1），在三名男子和一名女子（平均年龄为44岁）中，有外伤（n = 2）或进行性肩痛（n = 2）的临床病史被确认为急性和II级急性损伤（n = 1）。在一半的病例中，同时存在部分（n = 1）或全部（n = 1）厚度的棘上肌上肌腱插入撕裂。III级肌腱交界处损伤中肌腱交界处的张力丧失导致严重的萎缩和棘上前上肌的脂肪浸润。结论上颌肌肌腱交界处损伤在MRI中不常见。这些病变总是累及棘上肌的前束，并可能伴有插入性肌腱撕裂。严重的慢性损伤会导致棘上前肌选择性萎缩和脂肪浸润。有外伤（n = 2）或进行性肩痛（n = 2）的临床病史（44岁）。在一半的病例中，同时存在部分（n = 1）或全部（n = 1）厚度的棘上肌上肌腱插入撕裂。III级肌腱交界处损伤中肌腱交界处的张力丧失导致严重的萎缩和棘上前上肌的脂肪浸润。结论MRI对上睑肌强直性结节损伤并不常见。这些病变总是累及棘上肌的前束，并可能伴有插入性肌腱撕裂。严重的慢性损伤会导致棘上前肌选择性萎缩和脂肪浸润。有外伤（n = 2）或进行性肩痛（n = 2）的临床病史（44岁）。在一半的病例中，同时存在部分（n = 1）或全部（n = 1）厚度的棘上肌上肌腱插入撕裂。III级肌腱交界处损伤时肌腱交界处的张力丧失导致严重的萎缩和棘上前肌的脂肪浸润。结论上颌肌肌腱交界处损伤在MRI中不常见。这些病变总是累及棘上肌的前束，并可能伴有插入性肌腱撕裂。严重的慢性损伤会导致棘上前肌选择性萎缩和脂肪浸润。在一半的病例中，同时存在部分（n = 1）或全部（n = 1）厚度的棘上肌上肌腱插入撕裂。III级肌腱交界处损伤时肌腱交界处的张力丧失导致严重的萎缩和棘上前肌的脂肪浸润。结论上颌肌肌腱交界处损伤在MRI中不常见。这些病变总是累及棘上肌的前束，并可能伴有插入性肌腱撕裂。严重的慢性损伤会导致棘上前肌选择性萎缩和脂肪浸润。在一半的病例中，同时存在部分（n = 1）或全部（n = 1）厚度的棘上肌上肌腱插入撕裂。III级肌腱交界处损伤中肌腱交界处的张力丧失导致严重的萎缩和棘上前上肌的脂肪浸润。结论上颌肌肌腱交界处损伤在MRI中不常见。这些病变总是累及棘上肌的前束，并可能伴有插入性肌腱撕裂。严重的慢性损伤会导致棘上前肌选择性萎缩和脂肪浸润。III级肌腱交界处损伤中肌腱交界处的张力丧失导致严重的萎缩和棘上前上肌的脂肪浸润。结论上颌肌肌腱交界处损伤在MRI中不常见。这些病变总是累及棘上肌的前束，并可能伴有插入性肌腱撕裂。严重的慢性损伤会导致棘上前肌选择性萎缩和脂肪浸润。III级肌腱交界处损伤时肌腱交界处的张力丧失导致严重的萎缩和棘上前肌的脂肪浸润。结论上颌肌肌腱交界处损伤在MRI中不常见。这些病变总是累及棘上肌的前束，并可能伴有插入性肌腱撕裂。严重的慢性损伤会导致棘上前肌选择性萎缩和脂肪浸润。