For a PA cranial projection, the
1)midsagittal plane is positioned parallel with the IR.
2)OML is aligned perpendicular to the IR.
3)central ray is aligned perpendicular to the IR.
4)central ray is centered to the nasion.
A) 1 and 3 only
B) 2 and 3 only
C) 2, 3, and 4 only
D) 1 and 4 only

Question

Quizplus · Accepted Answer

For a PA cranial projection, the OML (orbitomeatal line) should be aligned perpendicular to the IR, and the central ray should also be aligned perpendicular to the IR. The central ray should be directed to the midpoint of the line connecting the nasion and inion. The midsagittal plane does not need to be parallel with the IR, and centering to the nasion alone is not sufficient. Therefore, choices 1 and 4 are incorrect, while choices 2 and 3 are correct. The correct answer is B, 2 and 3 only.

For a PA Cranial Projection, the