Describe four radiographic findings of tuberculous arthritis.

1. Phemister triad (osteoporosis, erosion at the joint margins, and cartilage destruction)
2. Gibbous deformity of the spine (secondary to vertebral body collapse)
3. Pott's disease (tuberculous disc space infection), a destructive process that spreads from the vertebral end plates to cross the intervertebral disc space, often affecting multiple levels
4. Paravertebral (psoas) abscesses