Which surface of the ankle is placed in contact with the IR for the upright lateral projection?

In the upright lateral projection of the ankle, the key focus is on positioning the ankle in such a way that the correct area is visualized for diagnostic imaging. The lateral surface of the ankle is the one that should be placed in contact with the image receptor (IR). This positioning allows for an accurate representation of the ankle joint, including the malleoli and the surrounding structures.

By placing the lateral surface of the ankle against the IR, the x-ray beam can penetrate through to produce a lateral view. This orientation is critical for assessing any potential fractures, joint alignment, and pathological conditions in that area. Thus, proper contact with the IR facilitates clear imaging of the anatomical structures required for interpretation by radiologists or medical professionals.

Choosing the medial, posterior, or anterior surfaces would not provide the same quality of visualization required for a lateral projection, therefore making them less appropriate for this specific imaging technique. Understanding the positioning of the patient and the orientation of the anatomical structures involved is essential in achieving optimal imaging outcomes in radiography.