In which plane should the CR be directed for an AP projection of the cervical spine?

For an AP (anterior-posterior) projection of the cervical spine, the central ray (CR) should be directed toward the mid-sagittal plane. This is because the mid-sagittal plane divides the body into equal left and right halves, allowing for a symmetrical view of the cervical spine when positioned appropriately. Aligning the CR with the mid-sagittal plane ensures that the entire cervical spine is visualized correctly and helps to minimize distortion and superimposition of anatomical structures.

When performing this projection, it's critical to ensure that the CR is perpendicular to the receptor and that the patient's midsagittal plane is aligned with the midline of the imaging receptor. This action guarantees that the various vertebrae are clearly defined, providing accurate diagnostic information.