This eight-year-old has had shoulder pain for approximately three months. She has a very week rotator cuff that makes little improvement with physical therapy. The pain is worse with tumbling. There is no impingement, drop arm or apprehension. No tenderness. Can you guess her original injury and why it’s relevant to the current diagnosis?
Her initial injury was a pulling-type injury sustained after a fall from a bicycle. The current diagnosis is brachial neuritis, which fits with this history. Make sure to notice the proton density hyperintensity within the supraspinatus and infraspinatus (arrow). Neurogenic myoedema can occur as early as 24-48 hours after a neural insult. Following this edematous period, the muscle may then undergo fatty infiltration.
Brachial neuritis can occur from traumatic impaction or a stretch injury. It may also be seen after an inflammatory neuropathy known as Parsonage-Turner syndrome. Myodema around the shoulder (involving its muscles) may also be seen in suprascapular notch impingement syndrome and quadrilateral space syndrome. For more shoulder review, check out MRI Online.