| Incidental findings | Iritis, distal arthritis |
| Signs | Question mark posture: loss of lumbar lordosis, fixed kyphosis, compensated extension cervical spine. Protruberant abdomen. |
| Differential diagnosis | Ankylosing spondylitis |
| Function | Ability to turn head |
| Tests |
Lower spine XR - Erosion,sclerosis sacroiliac joints / syndesmophytes / bamboo spine
HLA-B27 |