<unk>  is the displacement of one spinal vertebra compared to another. While some medical dictionaries define<unk>  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.<unk>  is graded based upon the degree of slippage of one vertebral body relative to the subsequent adjacent vertebral body.<unk>  is classified as one of the six major etiologies: degenerative, traumatic, dysplastic, isthmic, pathologic, or post-surgical.<unk>  most commonly occurs in the lumbar spine, primarily at the L5-S1 level with the L5 vertebral body anteriorly translating over the S1 vertebral body.
Spondylolisthesis
Retrolisthesis
Discitis
Disc protrusion
Spinal fracture
Vertebral compression fracture
Fibrous ankylosis
Vertebral osteomyelitis