Sacroiliitis refers to the inflammation of one or both sacroiliac joints located where the lower spine and pelvis meet. This condition can cause pain in the lower back or buttocks, and it may also radiate down one or both legs.

Diagnosing sacroiliitis can be challenging as it can be misidentified as other sources of lower back pain. This condition has been associated with a cluster of conditions that trigger inflammatory arthritis of the spine.



Pain caused by sacroiliitis is typically concentrated in the lower back and buttocks but may also affect the legs, groin, and feet. Activities that may exacerbate sacroiliitis pain include:

  • Prolonged standing
  • Bearing more weight on one leg than the other
  • Stair climbing
  • Running
  • Taking large strides