What is the correct direction for the central ray for a right posterior oblique (RPO) position of the cervical spine?

In a right posterior oblique (RPO) position of the cervical spine, the central ray is directed 15-20 degrees cephalad. This positioning is important for adequately visualizing the intervertebral foramina, particularly on the side opposite to the oblique position.

When a patient is in the RPO position, the cervical vertebrae being examined are angled away from the x-ray beam. The cephalad angle helps to better project the area of interest into the imaging plane, reducing superimposition of adjacent structures, and allowing for clearer visualization of the foramina on the left side.

This method ensures that the anatomy is properly aligned with the direction of the central ray, which is essential for obtaining accurate diagnostic images.