Pars interarticularis defects are most commonly located in which region of the spine?

Pars interarticularis defects are most commonly located in which region of the spine?

• A. Cervical spine
• B. Thoracic spine
• C. Lumbar spine
• D. Sacral region

Answer: (C)

Pars interarticularis defects, or spondylolysis, arise from repetitive stress across the pars region. This area bears the greatest extension and shear loads in the spine, especially in the lumbar segment during activities like jumping, kicking, or hyperextension maneuvers common in athletes. Among the lumbar levels, the lower lumbar spine—particularly L5—absorbs the most stress, making defects there far more frequent than in other regions. Because of these biomechanics, the lumbar spine is the region most commonly affected, while the cervical and thoracic regions and the sacrum are much less commonly involved.

Pars interarticularis defects, or spondylolysis, arise from repetitive stress across the pars region. This area bears the greatest extension and shear loads in the spine, especially in the lumbar segment during activities like jumping, kicking, or hyperextension maneuvers common in athletes. Among the lumbar levels, the lower lumbar spine—particularly L5—absorbs the most stress, making defects there far more frequent than in other regions. Because of these biomechanics, the lumbar spine is the region most commonly affected, while the cervical and thoracic regions and the sacrum are much less commonly involved.