Spondylolysis

The breaking down (dissolution) of a portion of a bony building block of the spine (a vertebra).</P> The portion of the vertebra that is affected in spondylolysis is a bone segment called the pars interarticularis (which is part of a plate which is located, in technical terms, between the superior and inferior articular processes of a lumbar vertebra).

In spondylolysis, there is separation of the pars interarticularis.</P> Spondylolysis can be a cause of abnormal movement of the spine (called spondylolisthesis) and lead to localized back pain.