Case 2 Answer

Answer: Posterior humeral dislocation

Posterior should dislocations can be very difficult to see on the frontal projection. YOU NEED A ORTHOGONAL PROJECTION! be it axillary or scapular Y (as shown here).   Now you can see that the humeral head is not articulating with the glenoid fossa. Because it goes straight back, you may not see this on the frontal views!

ref: https://radiopaedia.org/articles/posterior-shoulder-dislocation?lang=us