For an AP atlas and axis projection,
1)the mandibular angles and the shoulders are positioned at equal distances from the IR.
2)the acanthiomeatal line is aligned parallel with the IR.
3)a 5-degree cephalad angulation is used.
4)an imaginary line connecting the upper occlusal plane and posterior occiput's inferior edge is aligned perpendicular to the IR.
A) 1 and 4 only
B) 1 and 3 only
C) 2 and 3 only
D) 1, 3, and 4 only

Question

Quizplus · Accepted Answer

Option 1 is correct because in the AP projection of atlas and axis, the mandibular angles and the shoulders must be positioned at equal distances from the IR.
Option 3 is correct because a 5-degree cephalad angulation is used to better visualize atlas and axis on the radiograph.
Option 4 is correct because an imaginary line connecting the upper occlusal plane and posterior occiput's inferior edge must be aligned perpendicular to the IR to get a proper and clear radiograph. Option 2 is incorrect because in the AP projection of atlas and axis, the acanthiomeatal line is not aligned parallel with the IR.

For an AP Atlas and Axis Projection