Which describes the proper method for positioning the humerus for an AP projection?

In an Anteroposterior (AP) projection of the humerus, the proper positioning is crucial to ensure that the resulting image is clear and diagnostic. The correct approach involves abducting the upper limb, which helps to open up the shoulder joint and provides a more natural alignment of the humerus with the image receptor (IR).

Positioning the elbow in an extended position facilitates the alignment of the entire humerus in the imaging field, avoiding any foreshortening that could distort the image. Additionally, having the humeral epicondyles parallel to the IR ensures that the image captures the humerus in its true anatomical relationships, providing a clear view of the distal and proximal portions of the bone without significant distortion.

The combination of these positioning techniques maximizes the detail and accuracy of the radiographic image of the humerus, making option D the accurate choice for the AP projection method.