The lateral view is taken with the elbow flexed 90 degrees. Note the following:

1. The radial head overlies much of the proximal ulna. The coronoid process can still be seen just proximal to the radial head.

2. The olecranon of the ulna will project into the olecranon fossa of the humerus during extension. The trochlear notch of the ulna can be delineated. It is easy to appreciate how flexion and extension occur here.

3. The radial head, neck and tuberosity are readily identified.