Which diagnosis shows three contiguous lumbar vertebrae involved with normal disc height on radiographic imaging?

• A. Osteoarthritis
• B. Ankylosing spondylitis
• C. Diffuse idiopathic skeletal hyperostosis (DISH)
• D. Scoliosis

Answer: (C)

Diffuse idiopathic skeletal hyperostosis (DISH) is known for flowing ossification along the anterior longitudinal ligament that runs across multiple adjacent vertebral levels, with the intervertebral disc spaces remaining well preserved. When you see three contiguous lumbar levels showing this anterior “flowing” calcification and the discs still have normal height, it fits the DISH pattern quite well. This preserved disc height helps distinguish DISH from other spine conditions that often cause disc degeneration or collapse.

In contrast, osteoarthritis of the spine usually presents with more focal degenerative changes at individual levels, such as disc space narrowing and facet joint changes, rather than a long continuous anterior ossification. Ankylosing spondylitis typically involves the sacroiliac joints and shows syndesmophytes that bridge across the intervertebral discs, often with eventual fusion and less preserved disc height. Scoliosis describes a lateral curvature of the spine rather than a pattern of anterior ossification across several levels.