Where should the central ray be directed for an AP cervical X-ray?

For an AP cervical X-ray, the central ray should be directed at the level of the top aspect of the thyroid cartilage, which corresponds to approximately C4-C5 vertebrae. This positioning is crucial because it aligns the central ray with the cervical spine's midline and ensures optimal visualization of the cervical vertebrae as well as surrounding anatomical structures.

The thyroid cartilage serves as a reliable landmark since it is palpable and has consistent anatomical relationships with the cervical vertebrae. This allows for a standardized approach across different patients regardless of individual anatomical variations. Proper positioning of the central ray is important in obtaining clear images for accurate diagnosis and treatment planning.

While other landmarks may seem relevant, they do not align with the specific requirements for an AP cervical projection, which focuses on capturing the vertebrae at the appropriate anatomical location.