Which radiographic finding represents advanced Ankylosing Spondylitis?

• A. Bamboo spine
• B. Erosions of MCP joints
• C. Joint space narrowing of hips
• D. Calcified menisci

Answer: (A)

In advanced Ankylosing Spondylitis the spine undergoes extensive new bone formation along the spinal ligaments and annulus fibrosus, causing the vertebral bodies to fuse together. This creates a rigid, column-like spine with bridging bony formations between adjacent vertebrae. On radiographs, these bridging syndesmophytes give a continuous, vertical “streaked” appearance across many levels, producing the classic bamboo spine. This finding specifically reflects widespread ankylosis and is the hallmark of advanced disease.

Erosions of the MCP joints are more typical of rheumatoid arthritis, not AS. Joint space narrowing of the hips can occur in various inflammatory or degenerative conditions but isn’t characteristic of advanced AS. Calcified menisci indicate calcification within knee menisci, which isn’t a feature of axial spine fusion seen in AS.