Which of the following lines must be perpendicular to the IR for the AP "open mouth" atlas and axis?
A) Glabellomeatal line
B) Orbitomeatal line
C) Acanthiomeatal line
D) A line drawn from the lower edge of the upper incisors to the tip of the mastoid process

Question

Quizplus · Accepted Answer

The line drawn from the lower edge of the upper incisors to the tip of the mastoid process must be perpendicular to the IR for the AP "open mouth" view of the atlas and axis to ensure proper visualization of the odontoid process.

Which of the Following Lines Must Be Perpendicular to the IR