What indicates accurate positioning in a lateral projection of the humerus?

Accurate positioning in a lateral projection of the humerus is indicated by superimposed humeral epicondyles. This alignment ensures that the humerus is positioned correctly for a true lateral view. When the epicondyles are superimposed, it indicates that the arm is appropriately rotated, allowing for the optimal visualization of the anatomy.

In a lateral projection, the alignment of the epicondyles is essential because it helps to confirm that there is no obliquity present in the image. Any deviation in the rotation can lead to misinterpretation of the anatomy and potential diagnostic errors. This aspect of lateral positioning is crucial for radiologists and clinicians who depend on these images for accurate assessment of the humerus and related structures.

While other factors such as visual clarity of the lesser tubercle, the profile of the radial head, and the degree of elbow flexion can provide useful information regarding the arm position or the quality of the image, they do not specifically confirm the lateral positioning of the humerus itself as definitively as the superimposed epicondyles do.