Final answer:
A posterior oblique L-spine x-ray primarily demonstrates the intervertebral foramina, which are the openings allowing for the passage of spinal nerves.
Step-by-step explanation:
On a posterior oblique L-spine x-ray, the intervertebral foramina are demonstrated. This view is particularly useful for visualizing the lateral spaces where spinal nerves exit the spinal column. These foramina are bounded by the vertebral pedicles above and below, and the intervertebral discs contribute to their anterior boundaries.
For clarity, the other structures described such as the spinous process, the superior and inferior articular processes, and the transverse processes serve as important muscle attachment sites and contribute to the movement and articulation of the spine. However, the posterior oblique view is optimized to display the intervertebral foramina rather than these processes.