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So this is a 39-year-old baseball coach

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who is having pain while throwing.

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Let's start with the oblique coronal sequence.

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And the first thing that jumps to our eye is hypertrophic

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osteoarthritis of the acromioclavicular joint.

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There is also lateral downward slanting of the acromion.

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You see the inclination of the acromion is laterally tilted.

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And that is causing contact of the undersurface of

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the acromion with the bursal surface of the cuff.

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So we have extending from posterior to anterior,

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the respin tendon coming to insert into the greater

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tuberosity here, and then more anteriorly, the

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supraspinatus tendon attaching to the greater tuberosity.

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We have frame of the bursal surface fibers

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outlined by laminar fluid in the subdeltoid burs.

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But there is no discrete partial

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thickness here of the rotator cuff.

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We definitely have external impingement due to

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lateral downward slanting of the acromion and also the

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presence of thickening of the coracoacromial ligament.

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So if we look at the oblique coronal images,

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this is your undersurface of the acromion.

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anterior, posterior, and the green arrow is pointing to

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the coracoacromial ligament, which is markedly thickened.

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So part of the coracoacromial arch is the

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coracoacromial ligament that plays a role in

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cases where there is external impingement, as in

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this patient, in the oblique coronal ligament.

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Non FAT SAT sequence, we can see better the orientation

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of the acromion, the lateral downward tilting,

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the presence of these very prominent osteophytes,

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and the deformity that the acromioclavicular

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joint is causing on the supraspinatus muscle here.

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So there's this indentation caused by

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mass effect of the acromioclavicular joint

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on the supraspinatus tendon and muscle.

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So, to summarize, we have a patient who has very good

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muscle health, his muscles are big, but he has a very

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tight coracoacromial arch related to the presence of

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acromioclavicular joint osteoarthritis with hypertrophic

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changes, lateral downward slanting of the acromion,

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and thickening of the coracoacromial ligament.