Spondylolisthesis is a condition in which a bone (vertebra) in the lower part of the spine slips forward and onto a bone below it.

In children, spondylolisthesis usually occurs between the fifth bone in the lower back (lumbar vertebra) and the first bone in the sacrum area. It is often due to a birth defect in that area of the spine.

In adults, the most common cause is degenerative disease (such as arthritis). The slip usually occurs between the fourth and fifth lumbar vertebrae.

Other causes of spondylolisthesis include stress fractures (commonly seen in gymnasts) and traumatic fractures. Spondylolisthesis may occasionally be associated with bone diseases.

Spondylolisthesis may vary from mild to severe. It can produce increased lordosis (swayback), but in later stages may result in kyphosis (roundback) as the upper spine falls off the lower spine.

Symptoms may include lower back pain and pain in the thighs and buttocks, stiffness, muscle tightness, and tenderness in the slipped area. Neurological damage (leg weakness or changes in sensation) may result from pressure on nerve roots and may cause pain radiating down the legs.

• Lordosis
• Lower back pain
• Localized tenderness over the spine just above the pelvis
• Pain in thighs
• Pain in buttocks
• Tight hamstrings
• Stiffness in back

• X-ray of the spine (demonstrates misalignment of lumbar vertebra, and possible fracture)
• A straight leg raise may be uncomfortable or painful

NOTE: A person with spondylolisthesis may have no symptoms.