Which of the following is are true regarding radiographic examination of the acromioclavicular joints?

The radiograph illustrates an AP projection of the scapula; abduction of the arm moves the scapula away from the rib cage, revealing a greater portion of the scapula than would be visualized with the arm at the side.

A number of bony structures are identified: the acromion process (A), the humeral head (B), glenoid fossa (C), scapular spine (D), clavicle (E), supraspinatus fossa (F), acromioclavicular joint (G), scapular notch (H), coracoid process (I), inferior angle/apex (j), body/costal surface (K), lateral/axillary border (L).

When the arm is placed in the AP position, the epicondyles are parallel to the plane of the IR, and the shoulder is placed in external rotation. In this position, an AP projection of the humerus, elbow, and forearm can be obtained; it places the greater tubercle of the humerus in profile.

For the lateral projection of the humerus and the internal rotation projection of the shoulder, the arm is internally rotated, elbow somewhat flexed, with the back of the hand against the thigh, and the epicondyles are superimposed and perpendicular to the IR. The lateral projections of the humerus, elbow, and forearm all require that the epicondyles be perpendicular to the plane of the cassette.

How are the acromioclavicular articulations usually examined in order to demonstrate small separations?

Which of the following criteria is required for visualization of the greater tubercle in profile?

Which of the following should be demonstrated in a true AP projection of the clavicle?

In which of the following positions or projections will the subtalar joint be visualized?