The L5-S1 joint is a common site for which pathology?

• A. Osteoarthritis
• B. Spondylolisthesis
• C. Herniated disc
• D. Scoliosis

Answer: (B)

The L5–S1 region is a transition from a more mobile lumbar spine to a relatively fixed sacrum, so it experiences high shear forces. Spondylolisthesis means the vertebral body slips forward relative to the one below it, and at this level it’s especially common because defects in the pars interarticularis (isthmic spondylolisthesis) or degenerative changes weaken the posterior elements and allow forward displacement under load. This anterior slip can irritate or compress the nerve roots, which is why it’s a classic finding at L5–S1. Other conditions like facet joint osteoarthritis, disc herniation, or scoliosis can occur nearby, but the pathology most characteristically associated with the L5–S1 joint is spondylolisthesis.