Which of the following indicates poor alignment of the orbitomeatal line on a PA projection of the skull?

The correct choice signifies a specific outcome of poor alignment of the orbitomeatal line in a posteroanterior (PA) projection of the skull. When the orbitomeatal line is not properly aligned, it can lead to distortion in anatomical structures.

Internal acoustic meatus distortion indicates that there is misalignment because the internal acoustic meatus is reliant on accurate positioning for proper visualization on the radiograph. If the orbitomeatal line is off, the resulting image may not represent the true anatomy, leading to erroneous appearances like distortion of the internal acoustic meatus.

In contrast, while petrous ridge positions, frontal sinus opacity, and maxillary sinus enlargement can indicate other issues or variations in imaging, they are not as directly tied to the alignment of the orbitomeatal line. Proper alignments would not necessarily result in distortion of the internal acoustic meatus, making it a specific indicator of alignment issues in this context.