Rotation on a posteroanterior (PA) chest radiograph is demonstrated:

In the context of evaluating a posteroanterior (PA) chest radiograph, rotation of the patient can be identified by observing unequal distances between the sternoclavicular (SC) joints and the spine. When a patient is properly positioned for a PA chest radiograph, the SC joints should appear equidistant from the midline (spine). Any noticeable difference in the distances indicates that the patient may have rotated, which can affect the accuracy of the radiographic interpretation. This is crucial for proper alignment and to ensure that both lungs are equally visible and unobscured by any artifacts resulting from positioning errors.

The identification of rotation using the sternoclavicular joints is an essential technique in radiology. Additionally, rotation can cause misinterpretation of anatomical structures, leading to potential diagnostic errors. Recognizing this type of positioning error is fundamental in the practice of limited medical radiologic technology, helping ensure high-quality radiographic images for accurate assessments and diagnosis.