The left shoulder x-ray shows a light bulb contour of the humeral head. There is a trough like configuration of the antero-medial humeral head indicating an impaction fracture in this area (Reverse Hill Sach’s Lesion). Overall findings indicate the presence of a posterior shoulder dislocation. A trans-scapular shoulder view confirmed the presence of a posterior shoulder dislocation.

Further information including Radiological Signs in a posterior shoulder dislocation can be found here