Spondylolisthesis

Spondylolisthesis is the displacement of one vertebra compared to another. While some medical dictionaries define spondylolisthesis specifically as the forward or anterior displacement of a vertebra over the vertebra inferior to it (or the sacrum), it is often defined in medical textbooks as displacement in any direction. X-ray of measurement of spondylolisthesis at the lumbosacral joint, being 25% in this example.X-ray picture of a grade 1 isthmic anterolisthesis at L4-5MRI of L5-S1 anterolisthesisX-ray of a grade 4 anterolisthesis at L5-S1 with spinal misalignment indicatedAnterolisthesis L5/S1Anterolisthesis L5/S1Anterolisthesis L5/S1. Blue arrow normal pars interarticularis. Red arrow is a break in pars interarticularisAnterolisthesis L5/S1 Spondylolisthesis is the displacement of one vertebra compared to another. While some medical dictionaries define spondylolisthesis specifically as the forward or anterior displacement of a vertebra over the vertebra inferior to it (or the sacrum), it is often defined in medical textbooks as displacement in any direction. Olisthesis (synonym olisthy) is a term that more explicitly denotes displacement in any direction. Forward or anterior displacement can specifically be called anterolisthesis. Anterolisthesis commonly involves the fifth lumbar vertebra. Backward displacement is called retrolisthesis. Lateral displacement is called lateral listhesis or laterolisthesis. A hangman's fracture is a specific type of spondylolisthesis where the second cervical vertebra (C2) is displaced anteriorly relative to the C3 vertebra due to fractures of the C2 vertebra's pedicles.