Which term describes the SMV projection's path from under the chin to the vertex of the skull?

Which term describes the SMV projection's path from under the chin to the vertex of the skull?

• A. Townes projection
• B. Submentovertex projection
• C. Caldwell projection
• D. Waters projection

Answer: (B)

The path described is the Submentovertex projection. This projection is defined by directing the X-ray beam from under the chin (the submental region) up to the vertex at the top of the skull. That specific route is chosen because it provides a view of the skull base, foramen magnum, and related structures with the mandible and occipital bones less likely to obscure the image. In practice, the head is extended so the chin sits under the mandible and the vertex is aligned with the image receptor, with the central ray along the midline and perpendicular to the infrared-meatal line to traverse the base of the skull from below the chin to the top. Other named projections involve different routes and aims and do not describe this submental-to-vertex path.

The path described is the Submentovertex projection. This projection is defined by directing the X-ray beam from under the chin (the submental region) up to the vertex at the top of the skull. That specific route is chosen because it provides a view of the skull base, foramen magnum, and related structures with the mandible and occipital bones less likely to obscure the image. In practice, the head is extended so the chin sits under the mandible and the vertex is aligned with the image receptor, with the central ray along the midline and perpendicular to the infrared-meatal line to traverse the base of the skull from below the chin to the top. Other named projections involve different routes and aims and do not describe this submental-to-vertex path.