May also be called: Slipped Vertebra Spondylolisthesis (spon-duh-low-lis-THEE-sis) is when one of the vertebrae slips forward and out of place on the vertebra beneath it. More to Know There are nine vertebrae fused together to form the tailbone and 24 stacked on top of one another in the vertebral column. The five closest to the tailbone, where spondylolisthesis is typically found, are the lumbar vertebrae. When one of the vertebrae slips out of place in the column, it can cause back pain, muscle tightness, and long-term spinal problems. This can be a result of injury, repetitive stress, or a fracture in one of the vertebrae (spondylolysis). Keep in Mind Most people with spondylolisthesis get better by resting and doing exercises designed to stretch and strengthen the back. Only in rare cases is surgery needed to correct the condition. All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts. Back to Articles Related Articles Word! Vertebrae Reach around and feel those bumps in the center of your back. Read More Kyphosis Your spine, or backbone, normally curves forward gently as it runs up your back. Sometimes, though, someone's back can be rounded too far forward, which is a condition known as kyphosis. Read More Overuse Injuries Overuse (or repetitive stress) injuries happen when too much stress is placed on a part of the body, causing problems like swelling, pain, muscle strain, and tissue damage. Read More X-Ray Exam: Cervical Spine This X-ray can, among other things, help find the cause of neck, shoulder, upper back, or arm pain. It's commonly done after someone has been in an automobile or other accident. Read More Scoliosis Scoliosis makes a person’s spine curve from side to side. Large curves can cause health problems like pain or breathing trouble. Health care providers treat scoliosis with back braces or surgery when needed. Read More Spina Bifida Spina bifida is a birth defect that involves the incomplete development of the spinal cord or its coverings. It's usually detected before a baby is born and treated right away. Read More Kyphosis Everyone's spine is slightly rounded forward at a gentle angle. If this angle is too pronounced, more than 50 degrees or so, it's called kyphosis, also known as roundback or hunchback. Read More Your Bones Where would you be without your bones? Learn more about the skeletal system in this article for kids. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.