For a proper lateral view of the lumbar spine, what anatomical structure should be in profile?

In a proper lateral view of the lumbar spine, the anatomical structure that should be in profile is the spinous processes. This is crucial because the spinous processes are the bony projections on the back of the vertebrae, which become prominent and visible in a lateral radiographic image. When correctly positioned, the lateral view allows for clear visualization of these structures, helping to assess the alignment, pathology, or any deformities in the lumbar spine.

The spinous processes serve as important landmarks for evaluation and diagnosis, and their alignment relative to one another can indicate conditions such as scoliosis or other spinal irregularities. In contrast, while the transverse processes, sacrum, and iliac crests are also part of the anatomy visible in a lumbar lateral view, they do not specifically represent the aspect most relevant for assessing the lumbar spine as the spinous processes do.