When performing a lateral view of the thoracic spine, which of the following adjustments aids in proper positioning?

Placing the patient's arms above their head is critical when performing a lateral view of the thoracic spine as it helps to ensure that the spine is not obscured by the shoulder structures. This positioning provides a clearer view of the thoracic vertebrae and reduces any potential interference from the clavicles and shoulder girdles during the radiographic exam. By elevating the arms, you create a more optimal alignment for imaging the thoracic spine, allowing for the necessary anatomical details to be captured without obstruction.

In contrast, keeping the patient's knees straight does not directly impact the imaging of the thoracic spine in a lateral view, as this positioning pertains more to comfort and support. Lying prone is not appropriate for a lateral view; it changes the anatomical orientation and would not allow for the necessary visualization. Positioning the central ray (CR) at an angle could be relevant for different views or examinations, but for a standard lateral view of the thoracic spine, the CR should be perpendicular to the film.