Which basic projection of the elbow is best for demonstrating the trochlear notch in profile?

The lateral projection of the elbow is best for demonstrating the trochlear notch in profile. In this projection, the elbow is positioned at a 90-degree angle, allowing for a clear view of the anatomical structures of the elbow joint. The trochlear notch, which is part of the ulna, is better visualized in this position because it places the structures in a plane that makes the notch appear prominently outlined without overlapping.

In contrast, the other projections do not provide the same level of detail or clarity for evaluating the trochlear notch. The AP projection tends to show the entire elbow but does not focus on the profile of the notch. The medial oblique projection can help visualize some parts of the ulna and surrounding structures but does not present the trochlear notch as distinctly as the lateral view. The radial head projection is specifically designed to view the radial head and to assess for fractures, but it does not adequately demonstrate the trochlear notch in profile.