In a normal lateral lumbar spine X-ray, the following features should be visible and provide a baseline for healthy alignment and structure:

1. Vertebral Alignment: The vertebrae (L1-L5) should appear stacked in a straight line without any forward or backward displacement. The anterior and posterior borders of each vertebra should align smoothly, forming two continuous lines, which are indicators of proper vertebral alignment.

2. Disc Spaces: Intervertebral disc spaces should be uniform in height and well-maintained between each vertebra. There should be no narrowing, which could indicate degeneration.

3. Vertebral Body Shape: Each vertebral body should have a rectangular shape with smooth, intact edges and consistent height. There should be no signs of compression or wedging.

4. Spinous Processes: The spinous processes (posterior bony projections of each vertebra) should align in a straight line and have a regular spacing without any irregularities.

5. Facet Joints: The facet joints (where adjacent vertebrae meet) should appear normal, with no evidence of abnormal angulation

In a lateral lumbar spine X-ray of a patient with spondylolisthesis, the following abnormal features may be present:

1. Vertebral Alignment: One vertebra may appear displaced forward or backward in relation to the vertebra below it, disrupting the smooth alignment. This slippage is usually graded (Grade I to IV) based on how far the vertebra has moved forward, often measured in relation to the vertebra beneath it.

2. Disc Spaces: The intervertebral disc space at the level of the spondylolisthesis may appear reduced or uneven. Degenerative disc disease commonly accompanies spondylolisthesis, leading to narrowed disc spaces, especially in more advanced cases.

3. Vertebral Body Shape: The affected vertebra may appear slightly misshapen, particularly if degeneration is present. There may also be signs of sclerosis (increased bone density) or irregularities along the vertebral edges.

4. Spinous Processes: The spinous processes may appear misaligned, especially at the level of slippage. The normal straight line of spinous processes is often disrupted.

5. Pars Interarticularis Defect: In cases of isthmic spondylolisthesis, a defect or fracture in the pars interarticularis (the part of the vertebra between the superior and inferior articular processes) may be visible, which is commonly seen as a "collar" on the "Scotty dog" appearance of the vertebra on oblique views.

6. Facet Joints: The facet joints at the affected level may show signs of degeneration, appearing widened or irregular. Facet joint instability is often associated with spondylolisthesis and may contribute to the abnormal vertebral movement.