For the parietoacanthial projection, Waters method, of the nasal bones, the central ray exits through the:

• A. Nasion
• B. Ethmoid
• C. Acanthion
• D. Glabella

Answer: (C)

In this view, the central ray is aimed to exit through a landmark at the base of the nasal bridge—the acanthion. The Waters (parietoacanthial) projection is specifically positioned so the nasal bones are centered and not overlapped by other facial structures, which is achieved when the CR exits at the acanthion. Exiting through the acanthion places the ray right through the nasal bones themselves, producing a clear image of that area. If the ray exited through the nasion, ethmoid, or glabella, the projection would not align with the nasal bones for this view, leading to poor visualization or misrepresentation of the nasal region.