Spondylolisthesis is a condition where one vertebra slips over the vertebra below it. It can be caused by defects in the bone (congenital or acquired) or degeneration. Imaging like x-rays, CT, and MRI are used to classify and evaluate the spondylolisthesis. Patients experience back pain that worsens with activity and improves with rest. Treatment depends on the severity and cause of the spondylolisthesis.