Howdy,
The AC joint looks degenerative and the patient is 57 years old so this is common.
The trapezius muscle appearance is unusual,
I don’t think I have seen a trapezius tear before but perhaps you have just shown one to me.
Trapezius is such a big muscle I don’t think of it as being a muscle that tears.
The ultrasound appearance is more consistent with a delayed onset muscle soreness (DOMS) event rather than a tear.
Was there a history of repeated lifting on the day causing a muscle overloading injury?
Or was it a single lift?
Steve