Which condition is characterized by vertebrae sitting directly on top of each other?

The condition characterized by vertebrae sitting directly on top of each other is known as spondylolisthesis. This term refers specifically to a condition where one vertebra slips over another, which can lead to misalignment of the spine and may cause pain or discomfort due to nerve compression.

In cases of spondylolisthesis, the vertebra that slips forward can create an appearance of vertebrae directly stacked on top of each other, particularly when viewed from a lateral or side perspective. This misalignment can be caused by a variety of factors, including congenital defects, degenerative changes, or trauma.

Other related conditions describe different mechanisms of vertebral alignment. Spondylolysis, for example, refers to a defect or fracture in one of the vertebrae, while retrolisthesis indicates that a vertebra has moved backward relative to the one below it. Degenerative disc disease involves the deterioration of intervertebral discs but does not specifically indicate misalignment of vertebrae in the way that spondylolisthesis does. Understanding these distinctions is important for diagnosing and managing spinal conditions effectively.