Spondylolysis (spon-duh-LOL-uh-sis) is a defect of a narrow piece of bone (the pars interarticularis) in the vertebra.
The human spine is made up of 33 vertebrae — nine are fused together to form the tailbone (coccyx), and the other 24 are in the back. The lumbar vertebrae are in the lower back and closest to the tailbone, which is commonly where spondylolysis occurs.
Each vertebra has a ring of bone that forms part of the spinal canal. There are two narrow bridges of the ring called the pars interarticulari. Injuries or overuse can cause a fracture in this part of the vertebra, which can lead to persistent lower back pain.
Spondylolysis is more commonly seen in teens who overtrain in sports that can strain the lower back, like football, weightlifting, gymnastics, and wrestling.
If it's not allowed to heal properly, spondylolysis can lead to chronic back pain, loss in flexibility, and a painful condition called spondylolisthesis, which is when the vertebra slips out of place.
Most cases of spondylolysis heal just fine when diagnosed and treated early with rest, proper exercise that does not strain the lower back, and medication to help reduce the swelling.
All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.
