What is the relationship between the humeral epicondyles and the IR to achieve a proper lateral projection of the humerus?

For a proper lateral projection of the humerus, the relationship between the humeral epicondyles and the image receptor (IR) must be perpendicular. This positioning allows for the most accurate representation of the anatomical structures of the humerus in the lateral view. When the epicondyles are aligned perpendicularly to the IR, the resulting image captures the width of the humeral shaft without distortion, ensuring that the anatomy is presented correctly without overlap from adjacent structures.

In a lateral projection, achieving this perpendicular alignment is crucial for accurate diagnosis and assessment of the humerus, including evaluating any fractures or abnormalities in the bone structure. This standard positioning technique helps radiographers obtain clear and interpretable images, which are vital for effective medical imaging and subsequent treatment planning.