Which projection of the shoulder will demonstrate an open glenohumeral joint space and the glenoid process in profile?

The AP oblique projection, known as the Grashey method, is designed specifically to demonstrate an open glenohumeral joint space and to show the glenoid process in profile. In this projection, the patient is positioned at a 35 to 45-degree angle toward the affected side, which allows the glenoid cavity to be visualized clearly. This positioning opens up the joint space between the humeral head and the glenoid fossa, making it easier to assess any pathologies or abnormalities within the joint.

In contrast, the AP projection captures an overall view of the shoulder but does not adequately open the joint space or profile the glenoid. The lateral projection provides a different perspective, mainly focusing on the glenoid and scapula but often does not emphasize the joint space as effectively. The scapular Y projection is useful for assessing fractures and the positioning of the scapula but does not specifically provide a clear view of the glenohumeral joint space.

Thus, the Grashey method is the most appropriate choice for visualizing both the open joint space and the glenoid process in profile, making it the correct answer.