The medical condition, spondylolisthesis refers to:

Spondylolisthesis is specifically characterized by the forward displacement of one vertebra over another, which typically occurs in the lumbar region of the spine. This condition often results from a structural defect in the vertebra, trauma, degeneration, or abnormalities that lead to instability. It can be important in clinical settings, as it may cause pain, nerve compression, or other neurological symptoms. Recognizing the position of vertebrae and understanding how they can misalign assists healthcare providers in diagnosing and determining appropriate treatment strategies. The other options describe different spinal conditions or issues but do not accurately define spondylolisthesis itself.