Spondylolisthesis means the slipping of one vertebra over the top of the one below it. The vertebrae are the box-shaped bones that make up the spine.

What is going on in the body?

Normally, the vertebrae are stacked up and aligned with each other. Under certain circumstances, one vertebra may slip forward over the one below. This usually occurs in the lower back area, though the neck can also be affected.

What are the causes and risks of the condition?

Inborn defects, injury, or diseases may cause this condition. In adolescents, the most common cause is spondylolysis. In this condition, the bony arch of the vertebra of the low back is abnormally soft and able to slip easily. In the elderly, the most common cause is osteoarthritis in the spine. In this condition, the joints between the vertebrae become worn and unstable.

The following activities increase a person's risk for spondylolisthesis: