CR exits which surface landmark in Waters method for parietoacanthial projection?

CR exits which surface landmark in Waters method for parietoacanthial projection?

• A. Menton
• B. Acanthion
• C. Nasion
• D. Zygomatic arch

Answer: (B)

In the Waters parietoacanthial projection, the central ray is directed to exit at the acanthion. This exit point places the ray through the midface so the maxillary sinuses and orbital regions are projected with minimal superimposition of surrounding structures. The acanthion is the midpoint just below the nasal region, which aligns the CR with the facial midline and centers the structures of interest on the image. Choosing other landmarks like menton (chin), nasion (between the eyes at the root of the nose), or the zygomatic arch would misalign the ray for this view, leading to improper visualization or distortion of the midface structures.

In the Waters parietoacanthial projection, the central ray is directed to exit at the acanthion. This exit point places the ray through the midface so the maxillary sinuses and orbital regions are projected with minimal superimposition of surrounding structures. The acanthion is the midpoint just below the nasal region, which aligns the CR with the facial midline and centers the structures of interest on the image.

Choosing other landmarks like menton (chin), nasion (between the eyes at the root of the nose), or the zygomatic arch would misalign the ray for this view, leading to improper visualization or distortion of the midface structures.